Near-eye display system

ABSTRACT

An optical subsystem of a near-eye display system provides for projecting light of a virtual image of image content to an eye location, and provides for collecting light of the virtual image onto an exit pupil on a surface proximate to an outer surface of an eye when at the eye location. A subpupil modulator within an aperture in cooperation with the optical subsystem provides for forming a plurality of subpupils within the exit pupil, and provides for less than all of the light of the virtual image associated with one or more less than all of the plurality of subpupils to be projected to the eye location. In various independent aspects: at least two subpupils overlap by at least 20 percent; and the intensities of the subpupils are individually and independently controlled.

CROSS-REFERENCE TO RELATED APPLICATIONS

The instant application is a continuation of International ApplicationNo. PCT/US2022/032576 filed on 7 Jun. 2022, which claims benefit ofprior U.S. Provisional Application Ser. No. 63/197,777 filed on 7 Jun.2021, and claims benefit of prior U.S. Provisional Application Ser. No.63/222,978 filed on 17 Jul. 2021. Each of the above-identifiedapplications is incorporated herein by reference in its entirety.

BRIEF DESCRIPTION OF THE DRAWINGS

In the accompanying drawings:

FIG. 1 illustrates a schematic block diagram of a first aspect of anear-eye display system incorporating a flat-panel two-dimensionalimage-display array of light-emitting image-display pixels;

FIG. 2 illustrates a schematic diagram of the first aspect of thenear-eye display system illustrated in FIG. 1, illustrating anembodiment of a first aspect of an associated optical subsystemincorporating a plurality of lenses, absent the associated processor andcontroller elements;

FIG. 3 illustrates a plan view of the flat-panel two-dimensionalimage-display array of light-emitting image-display pixels of the firstaspect of the near-eye display system illustrated in FIGS. 1 and 2;

FIG. 4 illustrates a plan view of an aperture stop and a two-dimensionalmodulation array that respectively define an entrance pupil and anassociated plurality of modulated subpupils of the first-aspect near-eyedisplay system illustrated in FIGS. 1 and 2, with the two-dimensionalmodulation array controlled so as to provide for a first aspect of anassociated active subpupil region (ASR) in cooperation with an eye pupilof the user being centered on the optical axis of the associated opticalsubsystem;

FIG. 5 illustrates a plan view of an exit pupil and associated activeexit subpupils associated with the aperture stop and the two-dimensionalmodulation array of the first-aspect near-eye display system illustratedin FIGS. 1 and 2, for the active subpupil region (ASR) illustrated inFIG. 4;

FIG. 6 illustrates a plan view of the aperture stop and two-dimensionalmodulation array of the first-aspect near-eye display system illustratedin FIGS. 1 and 2, with the two-dimensional modulation array controlledso as to provide for the first aspect of an associated active subpupilregion (ASR) in cooperation with an eye pupil of the user being rotatedupwards and to the left relative to the optical axis of the associatedoptical subsystem;

FIG. 7 illustrates a plan view of an exit pupil and associated activeexit subpupils associated with the aperture stop and the two-dimensionalmodulation array of the first-aspect near-eye display system illustratedin FIGS. 1 and 2, for the active subpupil region (ASR) illustrated inFIG. 6;

FIG. 8 illustrates angular magnification provided for by an embodimentof the first aspect of the near-eye display system illustrated in FIGS.1 and 2;

FIG. 9 illustrates a longitudinal cross section of an associatedvolumetric visual environment of the first aspect of the near-eyedisplay system illustrated in FIGS. 1, 2 and 8, along the optical axisof the associated optical subsystem;

FIG. 10 illustrates a plan view of the aperture stop and two-dimensionalmodulation array of the first-aspect near-eye display system illustratedin FIGS. 1, 2, 8 and 9, with the two-dimensional modulation arraycontrolled so as to provide for a second aspect of an associated activesubpupil region (ASR) in cooperation with an eye pupil of the user beingrotated upwards and to the left relative to the optical axis of theassociated optical subsystem;

FIG. 11 illustrates a plan view of an exit pupil and associated activeexit subpupils associated with the aperture stop and two-dimensionalmodulation array of the first-aspect near-eye display system illustratedin FIGS. 1, 2, 8 and 9, for the active subpupil region (ASR) illustratedin FIG. 10;

FIG. 12 illustrates a plan view of the aperture stop and two-dimensionalmodulation array of the first-aspect near-eye display system illustratedin FIGS. 1, 2, 8 and 9, with the two-dimensional modulation arraycontrolled so as to provide for a third aspect of an associated activesubpupil region (ASR) in cooperation with an eye pupil of the user beingcentered on the optical axis of the associated optical subsystem;

FIG. 13 illustrates a plan view of an exit pupil and associated activeexit subpupil associated with the aperture stop and two-dimensionalmodulation array of the first-aspect near-eye display system illustratedin FIGS. 1, 2, 8 and 9, for the active subpupil region (ASR) illustratedin FIG. 12;

FIG. 14 illustrates a plan view of the aperture stop and two-dimensionalmodulation array of the first-aspect near-eye display system illustratedin FIGS. 1, 2, 8 and 9, with the two-dimensional modulation arraycontrolled so as to provide for the third aspect of an associated activesubpupil region (ASR) in cooperation with an eye pupil of the user beingrotated upwards and to the left relative to the optical axis of theassociated optical subsystem;

FIG. 15 illustrates a plan view of an exit pupil and associated activeexit subpupil associated with the aperture stop and two-dimensionalmodulation array of the first-aspect near-eye display system illustratedin FIGS. 1, 2 and 9, for the active subpupil region (ASR) illustrated inFIG. 14;

FIG. 16 illustrates a schematic block diagram of a second aspect of anear-eye display system incorporating a flat-panel two-dimensional arrayof light sources that define an associated array of modulated subpupilsof the second-aspect near-eye display system, in cooperation with aseparate flat-panel two-dimensional image-display array oflight-modulating image-display pixels;

FIG. 17 illustrates a schematic diagram of a portion of a firstembodiment of the second aspect of the near-eye display systemillustrated in FIG. 16, illustrating a first embodiment of a secondaspect of an associated optical subsystem incorporating a plurality oflenses, absent the associated processor and controller elements;

FIG. 18 illustrates a schematic block diagram of a third aspect of anear-eye display system incorporating a curved two-dimensional lightarray of light sources that define an associated array of modulatedsubpupils of the third-aspect near-eye display system, in cooperationwith a separate flat-panel array of light-modulating image-displaypixels;

FIG. 19 illustrates a schematic diagram of a portion of a firstembodiment of the third aspect of the near-eye display systemillustrated in FIG. 18, illustrating the first embodiment of the secondaspect of an associated optical subsystem incorporating a plurality oflenses, absent the associated processor and controller elements;

FIG. 20 illustrates a plan view of the flat-panel two-dimensionalimage-display array of light-modulating image-display pixels of thesecond and third aspects of the near-eye display system illustrated inFIGS. 16-19, 44, 45 and 47;

FIG. 21 illustrates a plan view of an aperture stop and atwo-dimensional modulation array that respectively define an entrancepupil and an associated plurality of modulated subpupils of each of thesecond—and third-aspect near-eye display systems illustrated in FIGS.16-19, 44, 45 and 47, with the two-dimensional modulation arraycontrolled so as to provide for the first aspect of an associated activesubpupil region (ASR) in cooperation with an eye pupil of the user beingcentered on the optical axis of the associated optical subsystem;

FIG. 22 illustrates a plan view of an exit pupil and associated activeexit subpupils associated with the aperture stop and a two-dimensionalmodulation array of each of the second—and third-aspect near-eye displaysystems illustrated in FIGS. 16-19, 44, 45 and 47, for the activesubpupil region (ASR) illustrated in FIG. 21;

FIG. 23 illustrates a plan view of the aperture stop and two-dimensionalmodulation array of each of the second—and third-aspect near-eye displaysystems illustrated in FIGS. 16-19, 44, 45 and 47, with thetwo-dimensional modulation array controlled so as to provide for thefirst aspect of an associated active subpupil region (ASR) incooperation with an eye pupil of the user being rotated upwards and tothe left relative to the optical axis of the associated opticalsubsystem;

FIG. 24 illustrates a plan view of an exit pupil and associated activeexit subpupils associated with the aperture stop and a two-dimensionalmodulation array of each of the second—and third-aspect near-eye displaysystems illustrated in FIGS. 16-19, 44, 45 and 47, for the activesubpupil region (ASR) illustrated in FIG. 23;

FIG. 25 illustrates a plan view of the aperture stop and two-dimensionalmodulation array of each of the second—and third-aspect near-eye displaysystems illustrated in FIGS. 16-19, 44, 45 and 47, with thetwo-dimensional modulation array controlled so as to provide for asecond aspect of an associated active subpupil region (ASR) incooperation with an eye pupil of the user being rotated upwards and tothe left relative to the optical axis of the associated opticalsubsystem;

FIG. 26 illustrates a plan view of an exit pupil and associated activeexit subpupils associated with the aperture stop and two-dimensionalmodulation array of each of the second—and third-aspect near-eye displaysystems illustrated in FIGS. 16-19, 44 and 45, for the active subpupilregion (ASR) illustrated in FIG. 25;

FIG. 27 illustrates a plan view of the aperture stop and two-dimensionalmodulation array of each of the second—and third-aspect near-eye displaysystems illustrated in FIGS. 16-19, 44 and 45, with the two-dimensionalmodulation array controlled so as to provide for a third aspect of anassociated active subpupil region (ASR) in cooperation with an eye pupilof the user being centered on the optical axis of the associated opticalsubsystem;

FIG. 28 illustrates a plan view of an exit pupil and associated activeexit subpupil associated with the aperture stop and two-dimensionalmodulation array of each of the second—and third-aspect near-eye displaysystems illustrated in FIGS. 16-19, 44 and 45, for the active subpupilregion (ASR) illustrated in FIG. 27;

FIG. 29 illustrates a plan view of the aperture stop and two-dimensionalmodulation array of each of the second—and third-aspect near-eye displaysystems illustrated in FIGS. 16-19, 44 and 45, with the two-dimensionalmodulation array controlled so as to provide for the third aspect of anassociated active subpupil region (ASR) in cooperation with an eye pupilof the user being rotated upwards and to the left relative to theoptical axis of the associated optical subsystem;

FIG. 30 illustrates a plan view of an exit pupil and associated activeexit subpupil associated with the aperture stop and two-dimensionalmodulation array of each of the second—and third-aspect near-eye displaysystems illustrated in FIGS. 16-19, 44 and 45, for the active subpupilregion (ASR) illustrated in FIG. 29;

FIG. 31 illustrates a schematic block diagram of a fourth aspect of anear-eye display system incorporating a scanned beam of light incooperation with a curved light-redirecting surface that together definean associated modulated subpupil of the fourth-aspect near-eye displaysystem, in cooperation with a separate flat-panel array oflight-modulating image-display pixels;

FIG. 32 illustrates a schematic diagram of a portion of a firstembodiment of the fourth aspect of the near-eye display systemillustrated in FIG. 31, illustrating the first embodiment of the secondaspect of an associated optical subsystem incorporating a plurality oflenses, absent the associated processor and controller elements;

FIG. 33 illustrates a plan view of the flat-panel two-dimensionalimage-display array of light-modulating image-display pixels of thefourth aspect of the near-eye display system illustrated in FIGS. 31 and32;

FIG. 34 illustrates a plan view of an aperture stop and the scanned beamof light redirected from the curved light-redirecting surface thatrespectively define an entrance pupil and a modulated subpupil of thefourth aspect of the near-eye display system illustrated in FIGS. 31, 32and 46, with the scanned beam of light controlled so as to provide forthe first aspect of an associated active subpupil region (ASR) incooperation with an eye pupil of the user being centered on the opticalaxis of the associated optical subsystem;

FIG. 35 illustrates a plan view of an exit pupil and associated exitsubpupil associated with the aperture stop and the scanned beam of lightredirected from the curved light-redirecting surface of the fourthaspect of the near-eye display system illustrated in FIGS. 31, 32 and46, for the active subpupil region (ASR) illustrated in FIG. 34;

FIG. 36 illustrates a plan view of an aperture stop and the scanned beamof light redirected from the curved light-redirecting surface thatrespectively define an entrance pupil and a modulated subpupil of thefourth aspect of the near-eye display system illustrated in FIGS. 31, 32and 46, with the scanned beam of light controlled so as to provide forthe first aspect of an associated active subpupil region (ASR) incooperation with an eye pupil of the user being rotated upwards and tothe left relative to the optical axis of the associated opticalsubsystem;

FIG. 37 illustrates a plan view of an exit pupil and associated exitsubpupil associated with the aperture stop and the scanned beam of lightredirected from the curved light-redirecting surface of the fourthaspect of the near-eye display system illustrated in FIGS. 31, 32 and46, for the active subpupil region (ASR) illustrated in FIG. 36;

FIG. 38 illustrates a plan view of an aperture stop and the scanned beamof light redirected from the curved light-redirecting surface thatrespectively define an entrance pupil and a modulated subpupil of thefourth aspect of the near-eye display system illustrated in FIGS. 31, 32and 46, with the scanned beam of light controlled so as to provide for asecond aspect of an associated active subpupil region (ASR) incooperation with an eye pupil of the user being rotated upwards and tothe left relative to the optical axis of the associated opticalsubsystem;

FIG. 39 illustrates a plan view of an exit pupil and associated exitsubpupil associated with the aperture stop and the scanned beam of lightredirected from the curved light-redirecting surface of the fourthaspect of the near-eye display system illustrated in FIGS. 31, 32 and46, for the active subpupil region (ASR) illustrated in FIG. 38;

FIG. 40 illustrates a plan view of an aperture stop and the scanned beamof light redirected from the curved light-redirecting surface thatrespectively define an entrance pupil and a modulated subpupil of thefourth aspect of the near-eye display system illustrated in FIGS. 31, 32and 46, with the scanned beam of light controlled so as to provide for athird aspect of an associated active subpupil region (ASR) incooperation with an eye pupil of the user being centered on the opticalaxis of the associated optical subsystem;

FIG. 41 illustrates a plan view of an exit pupil and associated exitsubpupil associated with the aperture stop and the scanned beam of lightredirected from the curved light-redirecting surface of the fourthaspect of the near-eye display system illustrated in FIGS. 31, 32 and46, for the active subpupil region (ASR) illustrated in FIG. 40;

FIG. 42 illustrates a plan view of an aperture stop and the scanned beamof light redirected from the curved light-redirecting surface thatrespectively define an entrance pupil and a modulated subpupil of thefourth aspect of the near-eye display system illustrated in FIGS. 31, 32and 46, with the scanned beam of light controlled so as to provide forthe third aspect of an associated active subpupil region (ASR) incooperation with an eye pupil of the user being rotated upwards and tothe left relative to the optical axis of the associated opticalsubsystem;

FIG. 43 illustrates a plan view of an exit pupil and associated exitsubpupil associated with the aperture stop and the scanned beam of lightredirected from the curved light-redirecting surface of the fourthaspect of the near-eye display system illustrated in FIGS. 31, 32 and46, for the active subpupil region (ASR) illustrated in FIG. 42;

FIG. 44 illustrates a schematic block diagram of a second embodiment ofthe second aspect of the near-eye display system incorporating aflat-panel two-dimensional array of light sources that define anassociated array of modulated subpupils of the second-aspect near-eyedisplay system, in cooperation with a separate flat-paneltwo-dimensional image-display array of light-modulating image-displaypixels, further illustrating a second embodiment of the second aspect ofan associated optical subsystem incorporating a free-form-surface/prismlens;

FIG. 45 illustrates a schematic block diagram of a second embodiment ofthe third aspect of a near-eye display system incorporating a curvedtwo-dimensional light array of light sources that define an associatedarray of modulated subpupils of the third-aspect near-eye displaysystem, in cooperation with a separate flat-panel array oflight-modulating image-display pixels, further illustrating the secondembodiment of the second aspect of an associated optical subsystemincorporating a free-form-surface/prism lens;

FIG. 46 illustrates a schematic block diagram of a second embodiment ofthe fourth aspect of a near-eye display system incorporating a scannedbeam of light in cooperation with a curved light-redirecting surfacethat together define an associated modulated subpupil of thefourth-aspect near-eye display system, in cooperation with a separateflat-panel array of light-modulating image-display pixels, furtherillustrating the second embodiment of the second aspect of an associatedoptical subsystem incorporating a free-form-surface/prism lens;

FIG. 47 illustrates a schematic block diagram of a third embodiment ofthe third aspect of a near-eye display system incorporating a curvedtwo-dimensional light array of light sources that define an associatedarray of modulated subpupils of the third-aspect near-eye displaysystem, in cooperation with a separate flat-panel array oflight-modulating image-display pixels further illustrating an embodimentof a third aspect of an associated optical subsystem incorporating anassociated conditioner lens and an associated first embodiment of amagnifier lens, each of which incorporate at least one Fresnel surface;

FIG. 48 illustrates a portion of a hypothetical embodiment of asecond-aspect near-eye display system, including the associated exitpupil, a Fresnel-surface magnifier lens and the associated flat-paneltwo-dimensional image-display modulation array, together with aray-trace simulation of light propagating from the flat-paneltwo-dimensional image-display modulation array through the magnifierlens to form a virtual image associated with the light entering the exitpupil during the process illustrated in FIG. 49 for determining aprescription of the associated magnifier lens;

FIG. 49 illustrates an embodiment of a process for determining theprescription of a magnifier lens of a near-eye display system;

FIG. 50 illustrates an embodiment of a process for determining aprescription of a conditioner lens of a near-eye display system;

FIG. 51 illustrates an embodiment of a hybrid magnifier lens of anear-eye display system;

FIG. 52 illustrates a schematic block diagram of a waveguide projectorlight source;

FIG. 53 illustrates a model of the waveguide projector illustrated inFIG. 52, incorporating a planar light source array in cooperation with acondenser lens, further illustrating the propagation of light rays fromthe planar light source array to and through the condenser lens;

FIG. 54 illustrates a schematic block diagram of a first embodiment of afifth aspect of a near-eye display system incorporating a waveguideprojector light source that defines an array of modulated subpupilsthereof, in cooperation with a separate flat-panel array oflight-modulating image-display pixels, further illustrating a thirdaspect of an associated optical subsystem incorporating the optics ofthe waveguide projector in cooperation with an associated conditionerlens and a magnifier lens, the conditioner and magnifier lenses of whichincorporate at least one Fresnel surface, further illustrating anincorporation of the hybrid magnifier lens illustrated in FIG. 51;

FIG. 55 illustrates a schematic block diagram of the first embodiment ofa fifth aspect of a near-eye display system as illustrated in FIG. 54,but with the associated waveguide projector replaced with the modelthereof illustrated in FIG. 53;

FIG. 56 illustrates a schematic block diagram of a second embodiment ofa fifth aspect of a near-eye display system incorporating a waveguideprojector light source that defines an array of modulated subpupilsthereof, as illustrated in FIG. 54, but further incorporating avarifocal lens between the associated waveguide projector and theassociated conditioner lens, further illustrating a fourth aspect of anassociated optical subsystem incorporating the optics of the waveguideprojector and the varifocal lens in cooperation with an associatedconditioner lens and a magnifier lens, the conditioner and magnifierlenses of which incorporate at least one Fresnel surface;

FIG. 57 illustrates a third embodiment of a fifth aspect of a near-eyedisplay system incorporating a waveguide projector light source thatdefines an array of modulated subpupils thereof, similar to thatillustrated in FIGS. 54 and 56, incorporating a fifth aspect of anoptical subsystem comprising a modified second-aspect optical subsystemfor which the combination of the controllable light source and theconditioner lens thereof is replaced with a waveguide projector, furtherillustrating an optional varifocal lens of an associated sixth aspect ofan optical subsystem;

FIG. 58 illustrates a general, fourth embodiment of a fifth aspect of anear-eye display system incorporating a waveguide projector light sourcethat defines an array of modulated subpupils thereof, similar to thatillustrated in FIGS. 54, 56 and 57, incorporating a seventh aspect of anoptical subsystem comprising a modified second-aspect optical subsystemfor which the combination of the controllable light source andconditioner lens thereof is replaced with a waveguide projector, furtherillustrating the incorporation of one or both of an optional conditionerlens and an optional varifocal lens;

FIG. 59a illustrates an example of a hypothetical intensity profile ofan active modulated subpupil illustrated in any of FIGS. 4, 6, 10, 12,14, 21, 23, 25, 27, 29, 34, 36, 38, 40, and 42 in respect of any of thefirst-through fifth-aspect near-eye display systems incorporatingidealized components operating under an idealized mode of operation;

FIG. 59b illustrates an example of a hypothetical intensity profile ofan active subpupil in an exit pupil image illustrated in in any of FIGS.5, 7, 11, 13, 15, 22, 24, 26, 28, 30, 35, 37, 39, 41, and 43 in respectof any of the first-through fifth-aspect near-eye display systemsincorporating idealized components operating under an idealized mode ofoperation;

FIG. 59c illustrates an example of a hypothetical intensity profile ofan active subpupil in an exit pupil image illustrated in FIG. 60 inrespect of any of the first-through fifth-aspect near-eye displaysystems incorporating realistic components subject to realisticconstraints and operating under a more realistic configuration and modeof operation relative to the configuration associated with FIG. 59 b;

FIG. 60 illustrates a plan view of an exit pupil and associated activeexit subpupils associated with the aperture stop and the two-dimensionalmodulation array of any of the first-, second-, third-, or fifth-aspectnear-eye display systems illustrated in FIGS. 1, 2, 16, 17, 18, 19, 44,45, 47, and 54 through 58, for the active subpupil region (ASR)illustrated in either of FIGS. 4 and 21;

FIG. 61 illustrates a first aspect of a process for controlling asubpupil modulator, which provides for activating a single subpupillocated closest to a central location an eye pupil of an eye beingilluminated by a near-eye display system;

FIG. 62 illustrates a process for mapping locations, lateral extents andintensity profiles of each of a plurality of subpupils for use by one ormore processes to control a subpupil modulator;

FIG. 63 illustrates a second aspect of a process for controlling asubpupil modulator that provides for deactivating subpupils for which asubstantial portion thereof is located outside of an eye pupil of an eyebeing illuminated by a near-eye display system;

FIG. 64 illustrates a hypothetical intensity profile of a plurality ofthe subpupils illustrated in FIG. 60, responsive to control inaccordance the second aspect of the process for controlling the subpupilmodulator;

FIG. 65 illustrates a hypothetical intensity profile of a plurality ofthe subpupils illustrated in FIG. 60, responsive to control inaccordance the third aspect of the process for controlling the subpupilmodulator;

FIG. 66 illustrates a third aspect of a process for controlling asubpupil modulator that provides for deactivating subpupils that are notproximate to a location of an eye pupil of an eye being illuminated by anear-eye display system, and for controlling an intensity of remainingsubpupils responsive to a location and extent of the eye pupil;

FIG. 67 illustrates a fourth aspect of a process for controlling asubpupil modulator that provides for controlling the intensities oflight through each of a plurality of subpupils responsive to apredetermined stored lookup table of subpupil intensity as a function ofthe location of the subpupil, and as a function of the location andextent of an eye pupil of an eye being illuminated by a near-eye displaysystem;

FIG. 68 illustrates a side view of a sixth aspect of a near-eye displaysystem incorporating a catadioptric magnifier, showing optical raytraces from three regions of an associated light-generating subpupilmodulator associated with the central and lateral extreme portions ofthe subpupil modulator;

FIG. 69 illustrates a side view of a sixth aspect of the near-eyedisplay system illustrated in FIG. 68, but showing optical ray tracesfrom only two regions of the associated light-generating subpupilmodulator associated with the central and one of the lateral extremeportions of the subpupil modulator; and

FIG. 70 illustrates a typical luminous intensity distribution of alight-emitting diode.

DETAILED DESCRIPTION

Referring to FIGS. 1-58, a near-eye display system 10 incorporates animage generator 12 that, in cooperation with an associated opticalsubsystem 14, provides for projecting light 16′ of an image 16 generatedby the image generator 12 onto an exit pupil 18 of the optical subsystem14, into the eye 20 of a user 22, and as a real image 16″ onto theretina 24 of the eye 20 for viewing by the user 22, wherein the exitpupil 18 of the optical subsystem 14 is located proximate to the frontsurface 20′ of the eye 20, the real image 16″ is associated with amagnified, apparently distant virtual image 16′″ of a two-dimensionalarray 26 of the image generator 12 that is the object of the image 16,and the exit pupil 18 comprises an image of an aperture stop 28 within,or associated with, the optical subsystem 14, wherein the aperture stop28 acts as an associated entrance pupil 28′ and provides forconstraining the lateral extent of the associated field of light 16′therewithin. The real image 16″ is projected onto the onto the retina 24of the eye 20 without vignetting by the optical subsystem 14,independent of the rotation of the user's eye 20 as a result of thatrotation providing for directing the center of the fovea of the eye 20to any location on the real image 16″.

The near-eye display system 10 further incorporates a subpupil modulator30 that is imaged by the optical subsystem 14 as an associatedexit-pupil image 18′ within the surface 18″ of the exit pupil 18. Thesubpupil modulator 30 provides defining one or more exit subpupils 32within the exit pupil 18, and provides for individually controlling thetransmission of light 16′ through each of the one or more exit subpupils32 and onto, or into, the eye 20. Each of the exit subpupils 32 isassociated with light 16′ of the image 16 propagating along acorresponding particular direction 34 at an associated angle relative tothe optical axis 36 of the associated optical subsystem 14, butotherwise contains light 16′ from each and every point of the image 16from which light 16′ emanates at that associated angle. For example,light 16.1′ (also designated by “A” in FIG. 1) associated with a firstgaze direction 34.1—that is generally along the optical axis 36 of theassociated optical subsystem 14—is imaged through a corresponding firstexit subpupil 32.1 that is also along the optical axis 36. Furthermore,light 16.2′ (also designated by “B” in FIG. 1) associated with a secondgaze direction 34.2—that has a first angular offset from the opticalaxis 36—is imaged through a corresponding second exit subpupil 32.2 thathas a corresponding first lateral offset from the optical axis 36. Yetfurther, light 16.3′ (also designated by “C” in FIG. 1) associated witha third gaze direction 34.3—that has a second angular offset from theoptical axis 36—is imaged through a corresponding third exit subpupil32.3 that has a corresponding second lateral offset from the opticalaxis 36.

The light 16′ of the image 16 is received by the eye 20 through an eyepupil 38 thereof, the opening of which is controlled by the iris 40, andthe angular orientation of which, along with that of the eye 20, isresponsive to the gaze direction 34 of the user 22. Although thetransverse extent of the exit pupil 18 is sufficiently large to providefor light 16′ of the image 16 to be viewed over a range of gazedirections 34, 34.1, 34.2, 34.3, for a particular gaze directions 34,34.1, 34.2, 34.3, only that portion of the light 16′ that is within theboundary of the edge of the eye pupil 38 will reach the retina 24 to beperceived as the image 16 by the user 22. The projected transverselocation and projected shape of the eye pupil 38 is responsive to theassociated gaze direction 34, 34.1, 34.2, 34.3 of that eye 20, rangingfrom a circular shape with no transverse offset relative to the opticalaxis 36 associated with the first gaze direction 34.1 when gazing alongthe optical axis 36, to an elliptical shape with an associatedtransverse offset relative to the optical axis 36 associated with othergaze directions 34, 34.2, 34.3. Light 16′ that is outside the edge ofthe eye pupil 38 will be backscattered by the surrounding tissue of theeye 20 or face of the user 22, thereby increasing ambient light whichmay reflect or scatter from components of the display system into theeye 20 that can otherwise degrade the quality of the image 16 beingintentionally viewed by the user 22. Accordingly, the near-eye displaysystem 10 incorporates an eye-tracking subsystem 42 comprising aninfrared illuminator 44 and an associated infrared-responsive camera 46in cooperation with an associated eye-tracking processor 48 thatprovides for tracking at least the lateral location of the eye pupil 38responsive to an image of the infrared light from the infraredilluminator 44 that is scattered by the iris 40 and received by theassociated infrared-responsive camera 46, and processed by theeye-tracking processor 48 to identify the edge of the eye pupil 38 andestimate the transverse location and transverse extent thereof, which isthen communicated to a subpupil modulation controller 50 that generatesan associated subpupil modulation control signal 51 that provides forcontrolling the activation of the associated modulated subpupils 32′ ofthe associated subpupil modulator 30 so as to activate one or moremodulated subpupils 32′ that provide for light 16′ of the image 16 to bereceived by the retina 24 of the eye 20 of the user 22, and so as toprovide for deactivating the remaining portion of the exit pupil 18 soas to prevent propagation of light 16′ therethrough, and thereby limitotherwise associated backscattering of light 16′ off the eye 20 or faceof the user 22.

For example, in one set of embodiments, the eye-tracking subsystem 42 inconfigured in accordance with one or more of the following Internetwebsites from the group consisting ofhttps://pupil-labs.com/products/core/;https://www.tobiipro.com/product-listing/hardware/;https://imotions.com/biosensor/eye-tracking-vr/;https://www.ergoneers.com/en/hardware/eye-tracking/;https://www.adhawkmicrosystems.com/eye-tracking/; andhttps://www.eye-square.com/en/headmounted-eye-tracking/. In one set ofembodiments, for which the near-eye display system 10 provides fordisplaying an image 16 to each eye 20 of the user 22, a singleeye-tracking subsystem 42 may be incorporated into the near-eye displaysystem 10 to provide for tracking for one of the eyes 20 of the user 22,with the resulting tracking information provided to the subpupilmodulation controller 50 for the other eye 20, based upon the assumptionthat the eye pupils 38 of both eyes 20 generally track to the samelocation in the image 16.

Referring to FIGS. 1-15, and to FIG. 3 in particular, in accordance witha first aspect 10.1 of a near-eye display system 10, 10.1, an associatedfirst aspect image generator 12, 12.1 comprises a flat-paneltwo-dimensional image-display array 52 of light-emitting image-displaypixels 54, each of which generates and emits, or transmits, —over arange of directions—the light 16′ of the image 16 from a correspondingpoint thereof. The light-emitting image-display pixels 54 can beembodied in various ways, for example, in one set of embodiments, aslight-emitting-diode (LED) elements, and in another set of embodiments,as backlit liquid-crystal-display (LCD) elements. Referring to FIGS. 1,2, 8 and 9, an associated first-aspect optical subsystem 14, 14.1 of thefirst-aspect near-eye display system 10, 10.1 comprises a pluralityof—for example, three—dioptric-power optical elements 56, 56.1, 56.2,56.3, for example, respective first 56.1′, L₁, second 56.2′, L₂, andthird 56.1′, L₃ convergent magnifier lenses, located along theassociated optical axis 36.

The first dioptric-power optical element 56, 56.1, 56.1′, L₁ is locatedbetween the flat-panel two-dimensional image-display array 52 and anassociated flat-panel two-dimensional modulation array 58 of anassociated first-aspect subpupil modulator 30, 30.1 of the first-aspectnear-eye display system 10, 10.1, with the first dioptric-power opticalelement 56, 56.1, 56.1′, L₁ separated by one focal length f₁ from eachof a first side 58.1 of the flat-panel two-dimensional modulation array58 and the subpupil modulator 30, 30.1, so that light 16′ emitted fromeach light-emitting image-display pixel 54 of the flat-paneltwo-dimensional image-display array 52 at a particular angle is focusedonto a corresponding particular transverse location on the flat-paneltwo-dimensional modulation array 58. The flat-panel two-dimensionalmodulation array 58 is located at or near the location of the aperturestop 28, wherein light 16′ from each of the light-emitting image-displaypixels 54 passes through the entirety of the aperture stop 28, or inother words, each location within the aperture stop 28 receives acomponent of light 16′ from each and every light-emitting image-displaypixel 54 of the flat-panel two-dimensional image-display array 52, i.e.each point on the associated image 16 that is generated by the imagegenerator 12, 12.1.

The flat-panel two-dimensional modulation array 58 incorporates aplurality of light-modulating pixels 60, for example, an array of liquidcrystal pixels 60′, wherein the intensity modulation of eachlight-modulating pixel 60 is independently controlled by the subpupilmodulation controller 50 responsive to a measure by the eye-trackingsubsystem 42 of the location of the eye pupil 38 relative to the exitpupil 18. For example, in one set of embodiments, the light-modulatingpixels 60 are controlled to one of two states, an ON state that providesfor enabling, and an OFF state that provide for blocking, thetransmission of light 16′ therethrough.

The second 56, 56.2, 56.2′, L₂ and third 56, 56.3, 56.3′, L₃dioptric-power optical elements—for example, corresponding second 56.2′,L₂ and third 56.3′, L₃ convergent magnifier lenses—of the opticalsubsystem 14, 14.1 are located between a second side 58.2 of theflat-panel two-dimensional modulation array 58 and the exit pupil 18 ofthe optical subsystem 14, 14.1, and together provide for forming animage at the exit pupil 18 of both the subpupil modulator 30,30.1/flat-panel two-dimensional modulation array 58 and the associatedaperture stop 28. For example, referring to FIG. 2, in accordance withone set of embodiments, a second convergent magnifier lens 56.2′, L₂located one focal length f₂ from the subpupil modulator 30,30.1/flat-panel two-dimensional modulation array 58 provides fortransforming light 16′ emanating from each location on the subpupilmodulator 30, 30.1/flat-panel two-dimensional modulation array 58 to acorresponding beam 64 of light 16′ propagating at a corresponding anglerelative to the optical axis 36; and a third convergent magnifier lens56.3′, L₃ located between the exit pupil 18 and the rear focal plane 62of the second convergent magnifier lens 56.2′, L₂, one focal length f₃from each, provides for transforming each beam 64 of light 16′ fromsecond convergent magnifier lens 56.2′, L₂ propagating at a particularangle relative to the optical axis 36 to a corresponding spot within theexit pupil 18. Furthermore, the first 56.1′, L₁, second 56.2′, L₂, andthird 56.1′, L₃ convergent magnifier lenses, in combination with thelens 66 of the eye 20, provide for forming the real image 16″ of theimage generator 12, 12.1/flat-panel two-dimensional modulation array 58on the retina 24 of the eye 20, wherein the third convergent magnifierlens 56.3′, L₃ provides for adjusting the focus and for adjusting theapparent distance of the virtual image 16′″ associated with the realimage 16″ that is formed on the retina 24 of the eye 20.

For example, light 16.1′ from each of the light-emitting image-displaypixels 54 of the flat-panel two-dimensional image-display array 52emitted in a direction that is substantially parallel with the opticalaxis 36 of the optical subsystem 14, 14.1, i.e. associated with thefirst gaze direction 34.1, is focused by the first dioptric-poweroptical element 56, 56.1, 56.1′, L₁ onto a first set of light-modulatingpixels 60.1 of the subpupil modulator 30, 30.1 at a central locationthereof associated with a first modulated subpupil 32.1′, wherein thecontrol state (i.e. ON or OFF) of the first set of light-modulatingpixels 60.1 controls whether or not that light 16.1′ can propagatetherethrough to become transformed to a first beam 64.1 of light 16.1′(also designated by “A” in FIG. 1) by the second dioptric-power opticalelement 56, 56.2, 56.2′, L₂, and then be focused by the thirddioptric-power optical element 56, 56.3, 56.3′, L₃ to form thecorresponding first exit subpupil 32.1 at a corresponding first location68.1 at the exit pupil 18, wherein the control state of the first set oflight-modulating pixels 60.1 is controlled by the subpupil modulationcontroller 50 responsive to whether the location of the eye pupil 38—asdetermined by the eye-tracking subsystem 42—is either aligned with, orsufficiently close to, infra, the first exit subpupil 32.1.

Furthermore, light 16.2′ from each of the light-emitting image-displaypixels 54 of the flat-panel two-dimensional image-display array 52emitted in a direction associated with the second gaze direction 34.2,is focused by the first dioptric-power optical element 56, 56.1, 56.1′,L₁ onto a second set of light-modulating pixels 60.2 of the subpupilmodulator 30, 30.1 at a first relatively offset location thereofassociated with a second modulated subpupil 32.2′, wherein the controlstate (i.e. ON or OFF) of the second set of light-modulating pixels 60.2controls whether or not that light 16.2′ can propagate therethrough tobecome transformed to a second beam 64.2 of light 16.2′ (also designatedby “B” in FIG. 1) by the second dioptric-power optical element 56, 56.2,56.2′, L₂, and then be focused by the third dioptric-power opticalelement 56, 56.3, 56.3′, L₃ to form the corresponding second exitsubpupil 32.2 at a corresponding second location 68.2 at the exit pupil18, wherein the control state of the second set of light-modulatingpixels 60.2 is controlled by the subpupil modulation controller 50responsive to whether the location of the eye pupil 38—as determined bythe eye-tracking subsystem 42—is either aligned with, or sufficientlyclose to, infra, the second exit subpupil 32.2.

Yet further, light 16.3′ from each of the light-emitting image-displaypixels 54 of the flat-panel two-dimensional image-display array 52emitted in a direction associated with the third gaze direction 34.3, isfocused by the first dioptric-power optical element 56, 56.1, 56.1′, L₁onto a third set of light-modulating pixels 60.3 of the subpupilmodulator 30, 30.1 at a second relatively offset location thereofassociated with a third modulated subpupil 32.3′, wherein the controlstate (i.e. ON or OFF) of the third set of light-modulating pixels 60.3controls whether or not that light 16.3′ can propagate therethrough tobecome transformed to a third beam 64.3 of light 16.2′ (also designatedby “C” in FIG. 1) by the second dioptric-power optical element 56, 56.2,56.2′, L₂, and then be focused by the third dioptric-power opticalelement 56, 56.3, 56.3′, L₃ to form the corresponding third exitsubpupil 32.3 at a corresponding third location 68.3 at the exit pupil18, wherein the control state of the third set of light-modulatingpixels 60.3 is controlled by the subpupil modulation controller 50responsive to whether the location of the eye pupil 38—as determined bythe eye-tracking subsystem 42—is either aligned with, or sufficientlyclose to, infra, the third exit subpupil 32.3.

Referring to FIGS. 4-7 and 11-14, the subpupil modulator 30, 30.1 iscontrolled by the subpupil modulation controller 50 in accordance with asubpupil modulation scheme 70 that provides for identifying an ActiveSubpupil Region (ASR) 72 of the subpupil modulator 30, 30.1 responsiveto the location, size, and possibly the shape, of the eye pupil 38 asdetermined by the eye-tracking subsystem 42, and responsive thereto,that generates a subpupil modulation control signal 51 that provides foractivating a subset of modulated subpupils 32′ within the ActiveSubpupil Region (ASR) 72 (i.e. by controlling to an ON state), and thatprovides for deactivating the remainder of the modulated subpupils 32′of the subpupil modulator 30, 30.1 (i.e. by controlling to an OFFstate), so as to provide for blocking light 16′ of the image 16 that isoutside the Active Subpupil Region (ASR) 72 from reaching the eye 20.

Referring to FIGS. 4-7, in accordance with a first aspect 70.1 of asubpupil modulation scheme 70, 70.1, the Active Subpupil Region (ASR) 72is set to a fixed size and shape that is sufficiently large to surroundthe eye pupil 38 regardless of the orientation of the eye 20, andregardless of the associated state of the iris 40, with accommodationfor the largest anticipated lateral extent of the eye pupil 38 andaccommodation of possible error in the determination of the location,size and/or shape of the eye pupil 38 by the eye-tracking subsystem 42,so as to mitigate against a potential uneven vignetting by an edge ofthe eye pupil 38 that might otherwise result if the edge of the eyepupil 38 were to not be fully illuminated by an associated exit subpupil32, for example, as might otherwise result from a misalignment betweenthe eye pupil 38 and the Active Subpupil Region (ASR) 72 that couldotherwise cause a spatial transition of the edge of the eye pupil 38from an active subpupil 32 inside the Active Subpupil Region (ASR) 72 toan inactive subpupil 32 outside the Active Subpupil Region (ASR) 72 forexample, as a result of relative motion between the eye pupil 38 and theActive Subpupil Region (ASR) 72. The location of the Active SubpupilRegion (ASR) 72 is continuously updated responsive to the eye-trackingsubsystem 42, at a rate of update sufficient to accommodate rotations ofthe eye 20 by the user 22 so that the exit subpupils 32 surrounding andwithin the eye pupil 38 are maintained in an active state. Referring toFIGS. 4 and 5, for the eye 22 of the user 22 rotated for viewing in thefirst gaze direction 34.1 as illustrated in FIG. 5, and as a result, adetection by the eye-tracking subsystem 42 of the eye pupil 38 beingcentered on the optical axis 36, the associated Active Subpupil Region(ASR) 72 determined by the subpupil modulation controller 50 isconcentric both with the eye pupil 38 and with the optical axis 36, witha diameter sufficiently greater than that of the eye pupil 38 so thatthe eye pupil 38 will be fully illuminated by active exit subpupils 32,wherein, as illustrated in FIG. 4, the light-modulating pixels 60 andassociated modulated subpupils 32′ within the Active Subpupil Region(ASR) 72 are activated by the subpupil modulator 30, 30.1, and theremaining modulated subpupils 32′ intersecting or outside of theboundary of the Active Subpupil Region (ASR) 72 are deactivated,resulting in the image 16 being presented to the eye 20 via only theactivated exit subpupils 32 that are associated with the activatedmodulated subpupils 32′, as illustrated in FIG. 5. Referring to FIGS. 6and 7, for the eye 22 of the user 22 rotated up and to the left asillustrated in FIG. 7, and as a result, a detection by the eye-trackingsubsystem 42 of an elliptically-shaped eye pupil 38 located up and tothe left of the associated optical axis 36, in accordance with thefirst-aspect subpupil modulation scheme 70, 70.1, the associated ActiveSubpupil Region (ASR) 72 determined by the subpupil modulationcontroller 50 is centered about the offset eye pupil 38, but with thesame diameter as illustrated in FIGS. 4 and 5, wherein, as illustratedin FIG. 6, the light-modulating pixels 60 and associated modulatedsubpupils 32′ within the Active Subpupil Region (ASR) 72 are activatedby the subpupil modulator 30, 30.1, and the remaining modulatedsubpupils 32′ intersecting or outside of the boundary of the ActiveSubpupil Region (ASR) 72 are deactivated, resulting in the image 16being presented to the eye 20 via only the activated exit subpupils 32that are associated with the activated modulated subpupils 32′ that arealigned with the eye pupil 38, as illustrated in FIG. 7. Accordingly,notwithstanding the resulting mitigation against uneven vignetting bythe eye pupil 38, the first-aspect subpupil modulation scheme 70, 70.1results in the illumination of a portion of the eye 20 surrounding theeye pupil 38 with extraneous light 16 ^(iv) that is then reflected orscattered by the front surface 20′ of the eye 20 rather than beingimaged onto the retina 24.

With the first 56.1′, L₁, second 56.2′, L₂, and third 56.1′, L₃convergent magnifier lenses positioned as illustrated in FIG. 2, avirtual image of the flat-panel two-dimensional image-display array 52by the first convergent magnifier lens 56.1′, L₁ is located at infinity,which becomes the object of the second convergent magnifier lens 56.2′,L₂, the image of which is then located at the rear focal plane 62 of thesecond convergent magnifier lens 56.2′, L₂, which becomes the object ofthe third convergent magnifier lens 56.3′, L₃, the virtual image 16′″ ofwhich is then located at infinity, which is projected onto the retina 24of the eye 20 for perception thereof by the user 22. Referring to FIG.8, the location of the third convergent magnifier lens 56.3′, L₃ can beadjusted to provide for an angularly-magnified virtual image 16′″located at a comfortable viewing distance.

During operation of the first-aspect near-eye display system 10, 10.1,an electronic image signal 74 is output from an associated displaycontroller 76 to the flat-panel two-dimensional image-display array 52for generating the image 16 thereupon, the light 16′ therefrom of whichilluminates, and, as described hereinabove, is subsequently processedby, the associated subpupil modulator 30, 30.1, wherein the electronicimage signal 74 is either based upon a signal 74′ received via anassociated wireless communication link 78, or is generated from a localimage source 74″, for example, either from a stored memory or from acamera.

Referring to FIG. 9, the near-eye display system 10, 10.1 provides for avolumetric visual environment (VVE) 80 between the user 22 and the imagegenerator 12 that is sufficiently large to enable the eye 20, whenpositioned at a comfortable distance from the image generator 12, toreceive unvignetted light 16′ from the entirety of the associatedvirtual image 16′″ regardless of the gaze direction 34 of the eye 20toward different points on that virtual image 16′″, so as to provide fora relatively large angular field of view provided by the virtual image16′″ of the image generator 12, particularly in support of greaterperceived immersion in that associated virtual environment. The fullvolumetric visual environment (VVE) 80—also referred to as the “eyebox”—can be adequately represented by a geometric surface construct 82within that volumetric visual environment (VVE) 80 as a result of thedistance from the eye 20 to the image generator 12 being relativelyfixed when the near-eye display system 10, 10.1 is attached to the user22, wherein the exit subpupils 32—located on an associated subpupilsurface 84 within the exit pupil 18—are located on, and constituteportions of, that geometric surface construct 82, with each exitsubpupil 32 being formed as a real image of a corresponding modulatedsubpupil 32′ formed by the subpupil modulator 30, 30.1.

In view of the volumetric visual environment (VVE) 80 providing forunvignetted viewing of the entire virtual image 16′″, any locationwithin the volumetric visual environment (VVE) 80, including thereforeany location on the associated subpupil surface 84 within or of thevolumetric visual environment (VVE) 80, and therefore any exit subpupil32 itself, will pass rays of light 16′ from the entirety of theassociated image 16 of the associated image generator 12, 12.1.Accordingly, for each point on the image generator 12, and for each exitpupil 18, there is at least one optical ray that can be geometricallytraced therebetween, and that would therefore also extend through eachcorresponding modulated subpupil 32′, because each exit subpupil 32 isan image of a corresponding modulated subpupil 32′. Accordingly, eachlight-modulating pixel 60 associated with a corresponding modulatedsubpupil 32′ represents a location in the optical subsystem 14, 14.1 foreither receiving light 16′ from the entirety of the image generator 12or from which light propagating in reverse would flood the entirety ofthe image generator 12.

The unvignetted virtual image 16′″ visible through any particular exitsubpupil 32 is referred to herein as a component image 86, with allcomponent images 86 perceived by the eye 20 at any given time—includingthose visually persisting—being referred to herein as the associatedcomposite image 88. For example, in the special case when the eye 20receives light 16′ from only one exit subpupil 32, the associatedcomposite image 88 will be given by the component image 86 as seenthrough that exit subpupil 32.

Each of the light-modulating pixels 60 of the flat-panel two-dimensionalmodulation array 58 is referred to herein generally as a modulationelement 90, which is located on an associated modulation surface 92.Generally, the modulation of light 16′ through a given modulationelement 90 refers to any means of partially or fully restricting theintensity of the component image 86 as perceived by the eye 20 throughthe exit subpupil 32 corresponding to that modulation element 90 suchas, for example, modulation or redirection of light 16′ incidentthereon, or, for example, in respect of the second through fourthaspects of the near-eye display system 10, 10.2, 10.3, 10.3, infra,modulation of light emanating from an associated modulation location.Any exit subpupil 32 for which the associated light throughput is mostlimited or restricted, i.e. for which the associated modulation element90 is in an OFF state, is referred to herein as having been deactivated,to being in a state of deactivation, or to being deactivated, whereasany lesser restriction that provides for a subsequent increase in theintensity of the component image 86 through the associated exit subpupil32 as perceived by the eye 20, up to and including the minimum level ofrestriction possible, is referred to herein as an “activation” of thatexit subpupil 32, resulting in that exit subpupil 32 as having beenactivated, to being in a state of activation, or to being activated.

Whereas a real image 16″ of the image generator 12, 12.1 is formed onthe retina 24 of the eye 20, that real image 16″ is perceived as amagnified virtual image 16′″ generally appearing some comfortabledistance from the user to minimize eye strain. As illustrated in FIG. 8,the optical rays passing through the volumetric visual environment (VVE)80 toward the eye 20 can be geometrically traced backwards withoutregard to the optical subsystem 14, 14.1 to locate the apparent locationof the virtual image 16′″.

The volumetric visual environment (VVE) 80 is the entire volume forwhich light 16′ from the entire image 16 passes through at any locationtherewithin, with the exit pupil 18 of the optical subsystem 14, 14.1being one possible associated aperture thereof, albeit the largestpossible such aperture. Accordingly, if the eye pupil 38 is locatedanywhere within that volumetric visual environment (VVE) 80, then theuser 22 will be able to see the entire image 16. The near-eye displaysystem 10 has an exit pupil 18 which, by definition, represents an imageof the aperture stop 28, beyond which light is restricted.

Referring to FIGS. 10 and 11, in accordance with a second aspect 70.2 ofa subpupil modulation scheme 70, 70.2, the Active Subpupil Region (ASR)72 is set to a variable size and shape that is adapted to besufficiently large so as to surround the eye pupil 38 regardless of theorientation of the eye 20, and regardless of the associated state of theiris 40, which—the same as for the first-aspect subpupil modulationscheme 70, 70.1, but accompanied by a lesser amount of extraneous light16 ^(iv)—also provides for mitigating against a potential unevenvignetting by an edge of the eye pupil 38 that might otherwise result ifthe edge of the eye pupil 38 were to not be fully illuminated by anassociated set of active exit subpupils 32. The location, size and shapeof the Active Subpupil Region (ASR) 72 is continuously updatedresponsive to the eye-tracking subsystem 42, at a rate of updatesufficient to accommodate rotations of the eye 20 by the user 22, sothat the exit subpupils 32 within and surrounding the eye pupil 38 aremaintained in an active state. Similar to that illustrated in FIGS. 4and 5, if the eye 22 of the user 22 is rotated for viewing in the firstgaze direction 34.1 as illustrated in FIG. 5, the resulting associatedActive Subpupil Region (ASR) 72 as determined by the subpupil modulationcontroller 50 is also concentric both with the eye pupil 38 and with theoptical axis 36, but with a relatively smaller diameter—relative to thatassociated with the first-aspect subpupil modulation scheme 70,70.1—that is sufficiently large to account for possible error in thedetermination of the location, size and/or shape of the eye pupil 38 bythe eye-tracking subsystem 42. Referring again to FIGS. 10 and 11, forthe eye 22 of the user 22 rotated up and to the left as illustrated inFIG. 11, and as a result, a detection by the eye-tracking subsystem 42of an elliptically-shaped eye pupil 38 located up and to the left of theassociated optical axis 36, in accordance with the second-aspectsubpupil modulation scheme 70, 70.2, the associated Active SubpupilRegion (ASR) 72 as determined by the subpupil modulation controller 50is centered about the offset eye pupil 38, but elliptically shaped,similar that of the eye pupil 38, wherein, as illustrated in FIG. 10,the light-modulating pixels 60 and associated modulated subpupils 32′within the Active Subpupil Region (ASR) 72 are activated by the subpupilmodulator 30, 30.1, and the remaining modulated subpupils 32′intersecting or outside of the boundary of the Active Subpupil Region(ASR) 72 are deactivated, resulting in the image 16 being presented tothe eye 20 via only the activated exit subpupils 32 that are associatedwith the activated modulated subpupils 32′ that are aligned with the eyepupil 38 of the near-eye display system 10 and within the ActiveSubpupil Region (ASR) 72, as illustrated in FIG. 11. Accordingly, as aresult of the Active Subpupil Region (ASR) 72 being dynamically sizedand shaped responsive to the size and shape of the eye pupil 38 asdetermined by the eye-tracking subsystem 42, the size and shape of theActive Subpupil Region (ASR) 72 can more closely match that of the eyepupil 38 while still mitigating against uneven vignetting by the edge ofthe eye pupil 38, which—in comparison with the first-aspect subpupilmodulation scheme 70, 70.1—results in a relatively lesser amount ofillumination of the portion of the eye 20 surrounding the eye pupil 38,and a corresponding relatively lesser amount of extraneous light 16^(iv) that is then reflected or scattered by the front surface 20′ ofthe eye 20 rather than being imaged onto the retina 24.

In accordance with a third aspect 70.3 of a subpupil modulation scheme70, 70.3, rather than making the Active Subpupil Region (ASR) 72 solarge as to avoid a spatial transition of the edge of the eye pupil 38from an active to an inactive exit subpupil 32, instead the ActiveSubpupil Region (ASR) 72 is constrained to a size that is smaller thanthat of the eye pupil 38, and aligned with the center of the eye pupil38 so as to prevent vignetting that could otherwise result with thepresence of such a spatial transition. Accordingly, the third-aspectsubpupil modulation scheme 70, 70.3 substantially eliminates anillumination of the portion of the eye 20 surrounding the eye pupil 38with extraneous light 16 ^(iv) that would otherwise be reflected orscattered by the front surface 20′ of the eye 20 rather than beingimaged onto the retina 24. Furthermore, a relatively smaller ActiveSubpupil Region (ASR) 72 provides for improving the perceived quality ofthe image 16 by decreasing the effective aperture size through which thelight 16′ passes into the eye 20, thereby decreasing the impact ofaperture-size-related optical aberrations, which increases the clarityof the image 16, which is particularly effective in a near-eye displaysystem 10, 10.1 that provides for a large field-of-view together withrelatively high magnification. Taken to the extreme—and similar to apinhole camera—the smallest Active Subpupil Region (ASR) 72 wouldcomprise a single exit subpupil 32 corresponding to a correspondingsingle modulation element 90 that is continuously identified to bestalign with the center of the eye pupil 38.

For example, referring to FIGS. 12 through 15, based upon an estimatefrom the eye-tracking subsystem 42 of the location of the center of theeye pupil 38, the subpupil modulation controller 50 identifies andactivates the modulated subpupil 32′—i.e. the associatedlight-modulating pixel 60—of an associated Active Subpupil Region (ASR)72, associated with the exit subpupil 32 that is most-closely alignedwith the eye pupil 38, and deactivates the remaining modulated subpupils32′/light-modulating pixels 60 of the subpupil modulator 30,30.1/flat-panel two-dimensional modulation array 58. The location of theActive Subpupil Region (ASR) 72 is continuously updated responsive tothe eye-tracking subsystem 42, at a rate of update sufficient toaccommodate rotations of the eye 20 by the user 22 so that only the oneor more exit subpupils 32 having corresponding one or more projectedtransverse locations within transverse projection of the eye pupil 38are maintained in an active state. Referring to FIGS. 12 and 13, for theeye 22 of the user 22 rotated for viewing in the first gaze direction34.1 as illustrated in FIG. 13, and as a result, a detection by theeye-tracking subsystem 42 of the eye pupil 38 being centered on theoptical axis 36, the associated Active Subpupil Region (ASR) 72determined by the subpupil modulation controller 50 is concentric bothwith the eye pupil 38 and with the optical axis 36, and, in one set ofembodiments, limited in size so as to encompass a corresponding singleexit subpupil 32, wherein, as illustrated in FIG. 12, thelight-modulating pixel 60 and associated modulated subpupil 32′ withinthe Active Subpupil Region (ASR) 72 is activated by the subpupilmodulator 30, 30.1, and the remaining modulated subpupils 32′ outsidethe boundary of the Active Subpupil Region (ASR) 72 are deactivated,resulting in the image 16 being presented to the eye 20 via only theactivated exit subpupil 32 associated with the activated modulatedsubpupil 32′, as illustrated in FIG. 13. Referring to FIGS. 14 and 15,for the eye 22 of the user 22 rotated up and to the left as illustratedin FIG. 15, and as a result, a detection by the eye-tracking subsystem42 of an elliptically-shaped eye pupil 38 located up and to the left ofthe associated optical axis 36, in accordance with the third-aspectsubpupil modulation scheme 70, 70.3, the associated Active SubpupilRegion (ASR) 72 determined by the subpupil modulation controller 50 islocated—for example, centered—within the offset eye pupil 38, wherein,as illustrated in FIG. 14, the light-modulating pixel 60 and associatedmodulated subpupil 32′ within the Active Subpupil Region (ASR) 72 isactivated by the subpupil modulator 30, 30.1, and the remainingmodulated subpupils 32′ outside the boundary of the Active SubpupilRegion (ASR) 72 are deactivated, resulting in the image 16 beingpresented to the eye 20 via only the activated exit subpupil 32associated with the activated modulated subpupil 32′, as illustrated inFIG. 15.

A number of practical considerations may impose a lower limit to thesize of the Active Subpupil Region (ASR) 72 used in the third-aspectsubpupil modulation scheme 70, 70.3. First, if the associated modulationsurface 92 incorporates an array of relatively-small modulation elements90, then there can be an increased complexity in the electronicmanufacturing and addressing of the correspondingly large number of suchelements corresponding to the exit subpupils 32 of the entire subpupilsurface 84. Second, a relatively smaller modulation element 90 such as alight-modulating pixel 60—or a light-source element, infra, —containedin array may be interleaved with relatively large gaps therebetween thatprovide for supporting electronic components and circuitry through whichno light is generated or passes, leading to discontinuities in theassociated subpupil surface 84 that is otherwise ideally associated witha relatively more continuous volumetric visual environment (VVE) 80.Third, there is a practical limit to how much light 16′ a singlemodulation element 90 can either pass—or generate, infra, —per unit areaof that modulation element 90, which under some circumstances couldpotentially otherwise limit the perceived intensity of the image 16 fromthat single modulation element 90 to a level less than desirable.Fourth, in respect of the fourth aspect of the near-eye display system10.4, infra, there are practical limits to both the minimal size andminimal light per unit area that can be generated by an associatedlight-source spot provided by a modulated light beam. Finally, theeffects of diffraction and scattering associated with relatively-smallmodulation elements 90 may act to increase the effective size of theActive Subpupil Region (ASR) 72.

Notwithstanding these practical considerations, an Active SubpupilRegion (ASR) 72 smaller than the eye pupil 38 can provide for improvedimage quality in a near-eye display system 10 with a relatively-largefield of view and a relatively-high magnification, the latter of whichcan provide for utilizing a relatively-smaller image generator 12, 12.1,relative to that provided for by the use of a relatively-larger ActiveSubpupil Region (ASR) 72. Even if the Active Subpupil Region (ASR) 72were to not be maintained entirely within the eye pupil 38 duringmomentary situations such as rapid eye rotation, manual user adjustmentsor bumping the near-eye display system 10, the resultant image 16 willsimply show some level of vignetting during those situations beforereturning to an unvignetted mode of operation after settling to a morestable environment.

If the size of the Active Subpupil Region (ASR) 72 is smaller than theminimal size of the eye pupil 38, then the iris 40 of the eye 20 will beineffectual in its normal biological function of modifying imageintensity changes through a biological change in the diameter of the eyepupil 38. This functionality can be replaced by adjusting overalltransmission through the Active Subpupil Region (ASR) 72 responsive to arestriction of the modulation range of all active modulation elements 90by the subpupil modulation controller 50 in accordance with the overallbrightness of the image content as indicated by polling either samples,or the entirety, of the pixel intensity values of the associatedelectronic image being displayed. For example, this modulation range canbe based upon a model of the biological pupillary response to light, forexample, based upon experimentally measuring the size of the eye pupil38 in response to the amount of light to which the eye 20 is exposed.Furthermore, the third-aspect subpupil modulation scheme 70, 70.3 canfurther provide for a calibration mode by which the eye pupil 38 isflooded with light—for example, in cooperation with an Active SubpupilRegion (ASR) 72 that exceeds the size of the eye pupil 38—for example,as provided for by either the first 70.1 or second 70.2 subpupilmodulation schemes 70, supra, —and utilizing measurements from theeye-tracking subsystem 42 of the size of the eye pupil 38 for varioustest images with various levels of brightness of the associatedillumination, and then limiting the maximum brightness of the light 16′of the image 16 to a level that resulted in the smallest diameter eyepupil 38 during the calibration mode, so as to provide for each user 22a brightness response that is customized to their particular physiology.

Referring to FIGS. 16-19, 31, and 32, in accordance with second 10.2,third 10.3 and fourth 10.4 aspects of a near-eye display system 10,10.2, 10.3, 10.4, an associated second-aspect image generator 12, 12.2comprises a flat-panel two-dimensional image-display modulation array 94of light-modulating image-display pixels 96—for example, liquid-crystallight-modulating image-display pixels 96′, for example, as illustratedin FIGS. 20 and 33—in cooperation with a controllable light source 97that provides for illuminating the entirety of the flat-paneltwo-dimensional image-display modulation array 94 from a controllablelocation, the latter of which provides for defining the associatedmodulated subpupil 32′.

Referring to FIGS. 16, 17 and 20-30, in accordance with the secondaspect 10.2 of the near-eye display system 10, 10.2, and an associatedfirst embodiment 10.2′ thereof, the controllable light source 97 isprovided for by a flat-panel two-dimensional light-source array 98 ofassociated light-source elements 100—for example, light-emitting-diodeelements 100′, or fiber-optic illuminator elements 100″, —with aconditioner lens 102, L₁ interposed between a first side 94.1 of theflat-panel two-dimensional image-display modulation array 94 and theflat-panel two-dimensional light-source array 98, for example, aplano-convex conditioner lens 102′, L₁, with the planar surface 102.1′thereof abutting the first side 94.1 of the flat-panel two-dimensionalimage-display modulation array 94 and located one focal length f₁ fromthe flat-panel two-dimensional light-source array 98. The second-aspectnear-eye display system 10, 10.2 incorporates an associatedsecond-aspect optical subsystem 14, 14.2 comprising the conditioner lens102, 102′, L₁ in combination with a second dioptric-power opticalelement 56, 56.2, 56.2′, L₁, for example, in accordance with a firstembodiment of the second-aspect optical subsystem 14, 14.2, 14.2′, asecond convergent magnifier lens 56.2′, L₂, each of which shares acommon optical axis 36.

Further in accordance with the second-aspect near-eye display system 10,10.2, 10.2′, the flat-panel two-dimensional light-source array 98constitutes an associated second-aspect subpupil modulator 30, 30.2,wherein each associated light-source element 100, 100′, 100″ constitutesthe associated modulation element 90 of the second-aspect near-eyedisplay system 10, 10.2, 10.2′ so as to provide for controlling anassociated modulated subpupil 32′. Each light-source element 100, 100′,100″ of the flat-panel two-dimensional light-source array 98 illuminatesthe entirety of the flat-panel two-dimensional image-display modulationarray 94 from a particular direction, and along a corresponding angle,associated with the location of that light-source element 100, 100′,100″ within the flat-panel two-dimensional light-source array 98.Accordingly, with the flat-panel two-dimensional light-source array 98located one focal length f₁ from the flat-panel two-dimensionalimage-display modulation array 94, the light 104 generated by eachlight-source element 100, 100′, 100″, and subsequentlyintensity-modulated by the flat-panel two-dimensional image-displaymodulation array 94, is transformed into a corresponding beam 64 oflight 16′ propagating at a corresponding angle relative to the opticalaxis 36.

During operation of the second-aspect near-eye display system 10, 10.2,10.2′, an electronic image signal 74 is output from an associateddisplay controller 76 to the flat-panel two-dimensional image-displaymodulation array 94 that in turn modulates the light 104 from theflat-panel two-dimensional light-source array 98 so as to provide forgenerating the image 16 therefrom, the light 16′ thereof of whichpropagates as one or more beams 64 of light 16′, each of which isassociated with a corresponding activated light-source element 100,100′, 100″—if activated—propagating at a corresponding angle relative tothe optical axis 36, wherein the electronic image signal 74 is eitherbased upon a signal 74′ received via an associated wirelesscommunication link 78, or is generated from a local image source 74″,for example, either from a stored memory or from a camera.

The second dioptric-power optical element 56, 56.2, 56.2′, L₂ incooperation with the conditioner lens 102, 102′, L₁ provide for formingan image of both the subpupil modulator 30, 30.2/flat-paneltwo-dimensional light-source array 98 and the associated aperture stop28, at the exit pupil 18 located proximate to the front surface 20′ ofthe eye 20 and associated with a corresponding planar subpupil surface84. For example, referring to FIGS. 16 and 17, in accordance with oneset of embodiments, the second convergent magnifier lens 56.2′, L₂ islocated one focal length f₂ from the image generator 12, 12.2/flat-paneltwo-dimensional image-display modulation array 94—i.e. from the secondside 94.2 of the flat-panel two-dimensional display-modulation array94—and provides for transforming each beam 64 of light 16′—propagatingat a corresponding angle relative to the optical axis 36—to acorresponding exit subpupil 32, associated with the correspondinglight-source element 100, 100′, 100″ of the flat-panel two-dimensionallight-source array 98, acting in cooperation with the entirety of theflat-panel two-dimensional image-display modulation array 94, as thecorresponding associated modulated subpupil 32′. Furthermore, the secondconvergent magnifier lens 56.2′, L₂, in combination with the lens 66 ofthe eye 20, provide for forming the real image 16″ of the imagegenerator 12, 12.2/flat-panel two-dimensional image-display modulationarray 94 on the retina 24 of the eye 20, wherein the second convergentmagnifier lens 56.2′, L₂ provides for adjusting focus and for adjustingthe apparent distance of the virtual image 16′″ associated with the realimage 16″ that is formed on the retina 24 of the eye 22.

For example, light 104 from an active—if activated—first light-sourceelement 100.1 at a central location of the flat-panel two-dimensionallight-source array 98 illuminates the entirety of the flat-paneltwo-dimensional image-display modulation array 94 and, in cooperationwith transformation by the conditioner lens 102, 102′, L₁, istransformed to a corresponding first beam 64.1 of light 16.1′, and thenbe focused by the second convergent magnifier lens 56.2′, L₂ to form thecorresponding first exit subpupil 32.1 at a corresponding first location68.1 at the exit pupil 18, wherein the control state of the firstlight-source element 100.1 is controlled by the subpupil modulationcontroller 50 responsive to whether the location of the eye pupil 38—asdetermined by the eye-tracking subsystem 42—is either aligned with, orsufficiently close to, infra, the first exit subpupil 32.1, wherein thecontrol state (i.e. ON or OFF) of the first light-source element 100.1controls whether or not light 104 from the first light-source element100.1 can illuminate the corresponding first exit subpupil 32.1. If theeye pupil 38 is either aligned with, or sufficiently close to, infra,the first exit subpupil 32.1, then the first light-source element 100.1is activated by the subpupil modulation controller 50 so as to cause theentirety of the image 16 from the perspective of the first exit subpupil32.1 to be presented to the eye 20 by the second-aspect near-eye displaysystem 10, 10.2, 10.2′. Otherwise, if the eye pupil 38 is not eitheraligned with, nor sufficiently close to, infra, the first exit subpupil32.1, then the first light-source element 100.1 is deactivated so thatthe first exit subpupil 32.1 is void of light 16.1′.

Furthermore, light 104 from an active—if activated—second light-sourceelement 100.2 at a first relatively offset location of the flat-paneltwo-dimensional light-source array 98 illuminates the entirety of theflat-panel two-dimensional image-display modulation array 94 and, incooperation with transformation by the conditioner lens 102, 102′, L₁,is transformed to a corresponding second beam 64.2 of light 16.2′, andthen be focused by the second convergent magnifier lens 56.2′, L₂ toform the corresponding second exit subpupil 32.2 at a correspondingsecond location 68.2 at the exit pupil 18, wherein the control state ofthe second light-source element 100.2 is controlled by the subpupilmodulation controller 50 responsive to whether the location of the eyepupil 38—as determined by the eye-tracking subsystem 42—is eitheraligned with, or sufficiently close to, infra, the second exit subpupil32.2, wherein the control state (i.e. ON or OFF) of the secondlight-source element 100.2 controls whether or not light 104 from thesecond light-source element 100.2 can illuminate the correspondingsecond exit subpupil 32.2. If the eye pupil 38 is either aligned with,or sufficiently close to, infra, the second exit subpupil 32.2, then thesecond light-source element 100.2 is activated by the subpupilmodulation controller 50 so as to cause the entirety of the image 16from the perspective of the second exit subpupil 32.2 to be presented tothe eye 20 by the second-aspect near-eye display system 10, 10.2, 10.2′.Otherwise, if the eye pupil 38 is not either aligned with, norsufficiently close to, infra, the second exit subpupil 32.2, then thesecond light-source element 100.2 is deactivated so that the second exitsubpupil 32.2 is void of light 16.2′.

Yet further, light 104 from an active—if activated—third light-sourceelement 100.3 at a second relatively offset location of the flat-paneltwo-dimensional light-source array 98 illuminates the entirety of theflat-panel two-dimensional image-display modulation array 94 and, incooperation with transformation by the conditioner lens 102, 102′, L₁,is transformed to a corresponding third beam 64.3 of light 16.3′, andthen be focused by the second convergent magnifier lens 56.2′, L₂ toform the corresponding third exit subpupil 32.3 at a corresponding thirdlocation 68.3 at the exit pupil 18, wherein the control state of thethird light-source element 100.3 is controlled by the subpupilmodulation controller 50 responsive to whether the location of the eyepupil 38—as determined by the eye-tracking subsystem 42—is eitheraligned with, or sufficiently close to, infra, the third exit subpupil32.3, wherein the control state (i.e. ON or OFF) of the thirdlight-source element 100.3 controls whether or not light 104 from thethird light-source element 100.3 can illuminate the corresponding thirdexit subpupil 32.3. If the eye pupil 38 is either aligned with, orsufficiently close to, infra, the third exit subpupil 32.3, then thethird light-source element 100.3 is activated by the subpupil modulationcontroller 50 so as to cause the entirety of the image 16 from theperspective of the third exit subpupil 32.3 to be presented to the eye20 by the second-aspect near-eye display system 10, 10.2, 10.2′.Otherwise, if the eye pupil 38 is not either aligned with, norsufficiently close to, infra, the third exit subpupil 32.3, then thethird light-source element 100.3 is deactivated so that the third exitsubpupil 32.3 is void of light 16.3′.

Referring again to FIG. 9, if the modulation surface 92 of the near-eyedisplay system 10, 10.1, 10.2, 10.2′ is implemented as a flat structureat the aperture stop 28 of the associated optical subsystem 14, 14.1,14.2, then the surface underlying the associated exit pupil 18 formed asthe image of the associated planar modulation surface 92, 92′ will alsobe flat, i.e. a planar subpupil surface 84, 84′, for example, asillustrated in FIG. 9 by the vertical dashed line bounded by the exitpupil 18. However, the image of any modulation surface 92 that is formedby the associated optical subsystem 14 within the associated volumetricvisual environment (VVE) 80 can also serve to modulate light 16′ throughthe image of that modulation surface 92. Accordingly, and alternatively,referring also to FIGS. 18 and 19, a concave-curved subpupil surface 84,84″ may be formed as the image of a corresponding curved modulationsurface 92, 92″—for example, with the latter formed as a curvedtwo-dimensional light-source array 106 of light-source elements 100 on,or associated with, an underlying concave-curved surface 107—wherein thecurvature of the curved modulation surface 92, 92″ may be configured sothat the resulting concave-curved subpupil surface 84, 84″ substantiallyconforms to the curvature of the front surface 20′ of the eye 20,thereby providing for the axial distance from the eye pupil 38 to theassociated concave-curved subpupil surface 84, 84″ to be substantiallyinvariant with respect to rotation of the eye 20, so as to provide forvisibility of exit subpupils 32 in their entirety without vignettingregardless of the rotation of the eye 20. Accordingly, positioning theexit subpupil 32 sufficiently close to the eye pupil 38 provides for allrays forming the component image 86 through that exit subpupil 32 topass through the eye pupil 38 without vignetting. Otherwise, as theaxial distance between the eye pupil 38 and a given exit subpupil 32increases, the periphery of the component image 86 through that exitsubpupil 32 is susceptible to eventually becoming increasingly vignettedby the edge of the eye pupil 38.

Referring again to FIG. 9, in accordance with the first- andsecond-aspect near-eye display system 10, 10.1, 10.2, 10.2′, for a rangeof rotations of the eye 20, the eye pupil 38 traces a concave geometricsurface construct 82, 82′, so that for either a flat-paneltwo-dimensional modulation array 58 of light-modulating pixels 60, or aflat-panel two-dimensional light-source array 98 of light-sourceelements 100, respectively, —wherein the flat nature thereof iscompatible with typical electronic device manufacturing approaches,—that provide for associated planar subpupil surfaces 84, 84′ of theassociated exit subpupils 32, the distance between the associated exitsubpupil 32 and the eye pupil 38 will change as the eye 20 rotates,thereby increasing the prospect of vignetting of the associatedcomponent images 86 as that distance increases, wherein the concavity ofthe concave geometric surface construct 82, 82′ is from the point ofview, and with respect to, the associated eye 20 of the user 22.

Referring to FIGS. 18-30, the third aspect 10.3 of the near-eye displaysystem 10, 10.3, and an associated first embodiment 10.3′ thereof, issubstantially the same as the second-aspect near-eye display system 10,10.2, 10.2′, supra, except that an associated third-aspect imagegenerator 12, 12.3 incorporates a controllable light source 97 thatincorporates a curved two-dimensional light-source array 106 oflight-source elements 100, 100′, 100″, instead of a flat-paneltwo-dimensional light-source array 98, which provides for an associatedcurved modulation surface 92, 92″. With the subpupil surface 84 being animage of the modulation surface 92, this results in a correspondingassociated concave-curved subpupil surface 84, 84″ that, referring toFIG. 9, conforms to a concave geometric surface construct 82, 82′defined by the front surface 20′ of the eye 20 over a range ofrotations, which provides for minimizing the variation in axial distancebetween the eye pupil 38 and any active exit subpupil 32 over a range ofpossible rotations of the eye 20. Referring to FIG. 19, in accordancewith one set of embodiments, the relatively outboard light-sourceelements 100, 100.2, 100.3 are located one focal length f₁ from theassociated first dioptric-power optical element 56, 56.1, 56.1′, L₁.

For example, the curved two-dimensional light-source array 106 oflight-source elements 100, 100′, 100″ may be embodied by either a curvedarray of independently controllable light sources, such aslight-emitting diodes; or of a flat array of such light-emitting diodes,with the light from each light-emitting diode coupled to one or moreentrances of one or more associated optical light pipes, thecorresponding exits of which are coupled to form an associatedlight-source element 100, 100′, 100″ that is operatively coupled to, ora part of, an underlying concave-curved surface 107 of curvedtwo-dimensional light-source array 106, so that the exits of these lightpipes collectively form the light-source elements 100, 100′, 100″ of thecurved two-dimensional light-source array 106.

Further in accordance with the third-aspect near-eye display system 10,10.3, 10.3′, the curved two-dimensional light-source array 106constitutes an associated third-aspect subpupil modulator 30, 30.3,wherein each associated light-source element 100, 100′, 100″ constitutesthe associated modulation element 90, similar to that of thesecond-aspect near-eye display system 10, 10.2, 10.2′ so as to providefor controlling an associated modulated subpupil 32′, but on anunderlying concave-curved surface 107. Each light-source element 100,100′, 100″ of the curved two-dimensional light-source array 106illuminates the entirety of the flat-panel two-dimensional image-displaymodulation array 94 from a particular direction, and along acorresponding angle, associated with the location of that light-sourceelement 100, 100′, 100″ within the curved two-dimensional light-sourcearray 106. Accordingly, with the curved two-dimensional light-sourcearray 106 located one focal length f₁ from the flat-paneltwo-dimensional image-display modulation array 94, the light 104generated by each light-source element 100, 100′, 100″, and subsequentlyintensity-modulated by the flat-panel two-dimensional image-displaymodulation array 94, is transformed into a corresponding beam 64 oflight 16′ propagating at a corresponding angle relative to the opticalaxis 36.

The second dioptric-power optical element 56, 56.2, 56.2′, L₂ incooperation with the conditioner lens 102, 102′, L₁ provide for forminga curved subpupil array image 108 of both the subpupil modulator 30,30.3/curved two-dimensional light-source array 106 and the associatedaperture stop 28, at the exit pupil 18 located proximate to the frontsurface 20′ of the eye 20 and associated with the correspondingconcave-curved subpupil surface 84, 84″.

The light 104 originating from each light-source elements 100, 100′,100″ is independently controlled, e.g. ON or OFF, by the subpupilmodulation controller 50 responsive to the eye-tracking subsystem 42 inthe same manner as described hereinabove for the second-aspect near-eyedisplay system 10, 10.2, 10.2′.

Referring to FIGS. 21-30, the second—and third-aspect subpupilmodulators 30, 30.2, 30.3 are controlled by the subpupil modulationcontroller 50 in accordance with a subpupil modulation scheme 70 thatprovides for identifying an Active Subpupil Region (ASR) 72 of thesubpupil modulator 30, 30.2, 30.3 responsive to the location, size, andpossibly the shape, of the eye pupil 38 as determined by theeye-tracking subsystem 42, and responsive thereto, that generates asubpupil modulation control signal 51 that provides for activating asubset of modulated subpupils 32′ within the Active Subpupil Region(ASR) 72 (i.e. by controlling to an ON state) by activating thecorresponding associated light-source elements 100, 100′, 100″, so as togenerate light 104 therefrom; and that provides for deactivating theremainder of the modulated subpupils 32′ of the subpupil modulator 30,30.2, 30.3 (i.e. by controlling to an OFF state), by deactivating thecorresponding associated light-source elements 100, 100′, 100″, so as tonot generate light 104 therefrom. In comparison with the first-aspectnear-eye display system 10, 10.1, for which the powering of thelight-emitting image-display pixels 54 of the entire flat-paneltwo-dimensional image-display array 52 is independent of which exitsubpupils 32 are activated, for the second—and third-aspect near-eyedisplay systems 10, 10.2, 10.2′, 10.3, 10.3′, only light-source elements100, 100′, 100″ associated with active exit subpupils 32 are powered,and the associated flat-panel two-dimensional image-display modulationarray 94 consumes only a negligible amount of power, which togethertherefor provides a substantial reduction in power consumption relativeto that of the first-aspect near-eye display system 10, 10.1.

Referring to FIGS. 21-23, in accordance with the first aspect 70.1 ofthe subpupil modulation scheme 70, 70.1, the Active Subpupil Region(ASR) 72 is set to a fixed size and shape that is sufficiently large tosurround the eye pupil 38 regardless of the orientation of the eye 20,and regardless of the associated state of the iris 40, withaccommodation for the largest anticipated lateral extent of the eyepupil 38 and accommodation of possible error in the determination of thelocation, size and/or shape of the eye pupil 38 by the eye-trackingsubsystem 42, so as to mitigate against a potential uneven vignetting byan edge of the eye pupil 38 that might otherwise result if the edge ofthe eye pupil 38 were to not be fully illuminated by an associated exitsubpupil 32, for example, as might otherwise result from a misalignmentbetween the eye pupil 38 and the Active Subpupil Region (ASR) 72 thatcould otherwise cause a spatial transition of the edge of the eye pupil38 from an active subpupil 32 inside the Active Subpupil Region (ASR) 72to an inactive subpupil 32 outside the Active Subpupil Region (ASR) 72,for example, as a result of relative motion between the eye pupil 38 andthe Active Subpupil Region (ASR) 72. The location of the Active SubpupilRegion (ASR) 72 is continuously updated responsive to the eye-trackingsubsystem 42, at a rate of update sufficient to accommodate rotations ofthe eye 20 by the user 22 so that the exit subpupils 32 surrounding andwithin the eye pupil 38 are maintained in an active state. Referring toFIGS. 21 and 22, for the eye 22 of the user 22 rotated for viewing inthe first gaze direction 34.1 as illustrated in FIG. 22, and as aresult, a detection by the eye-tracking subsystem 42 of the eye pupil 38being centered on the optical axis 36, the associated Active SubpupilRegion (ASR) 72 determined by the subpupil modulation controller 50 isconcentric both with the eye pupil 38 and with the optical axis 36, witha diameter sufficiently greater than that of the eye pupil 38 so thatthe eye pupil 38 will be fully illuminated by active exit subpupils 32,wherein, as illustrated in FIG. 21, the light-source elements 100, 100′,100″ and associated modulated subpupils 32′ within the Active SubpupilRegion (ASR) 72 are activated by the subpupil modulator 30, 30.2, 30.3,and the remaining modulated subpupils 32′ intersecting or outside of theboundary of the Active Subpupil Region (ASR) 72 are deactivated so as tothereby not consume power, resulting in the image 16 being presented tothe eye 20 via only the activated exit subpupils 32 that are associatedwith the activated modulated subpupils 32′, as illustrated in FIG. 22.Referring to FIGS. 23 and 24, for the eye 22 of the user 22 rotated upand to the left as illustrated in FIG. 24, and as a result, a detectionby the eye-tracking subsystem 42 of an elliptically-shaped eye pupil 38located up and to the left of the associated optical axis 36, inaccordance with the first-aspect subpupil modulation scheme 70, 70.1,the associated Active Subpupil Region (ASR) 72 determined by thesubpupil modulation controller 50 is centered about the offset eye pupil38, but with the same diameter as illustrated in FIGS. 21 and 22,wherein, as illustrated in FIG. 23, the light-source elements 100, 100′,100″ and associated modulated subpupils 32′ within the Active SubpupilRegion (ASR) 72 are activated by the subpupil modulator 30, 30.2, 30.3,and the remaining modulated subpupils 32′ intersecting or outside of theboundary of the Active Subpupil Region (ASR) 72 are deactivated so as tothereby not consume power, resulting in the image 16 being presented tothe eye 20 via only the activated exit subpupils 32 that are associatedwith the activated modulated subpupils 32′ that are aligned with the eyepupil 38, as illustrated in FIG. 24. Accordingly, notwithstanding theresulting mitigation against uneven vignetting by the eye pupil 38, thefirst-aspect subpupil modulation scheme 70, 70.1 results in theillumination of a portion of the eye 20 surrounding the eye pupil 38with extraneous light 16 ^(iv) that is then reflected or scattered bythe front surface 20′ of the eye 20 rather than being imaged onto theretina 24, although with benefit from a substantial reduction inelectrical power consumption compared with that required by the firstaspect near-eye display system 10, 10.1 to power the entire flat-paneltwo-dimensional image-display array 52 of light-emitting image-displaypixels 54,

Referring to FIGS. 25 and 26, in accordance with the second aspect 70.2of the subpupil modulation scheme 70, 70.2, the Active Subpupil Region(ASR) 72 is set to a variable size and shape that is adapted to besufficiently large surround the eye pupil 38 regardless of theorientation of the eye 20, and regardless of the associated state of theiris 40, which—the same as for the first-aspect subpupil modulationscheme 70, 70.1, but accompanied by a lesser amount of extraneous light16 ^(iv)—also provides for mitigating against a potential unevenvignetting by an edge of the eye pupil 38 that might otherwise result ifthe edge of the eye pupil 38 were to not be fully illuminated by anassociated exit subpupil 32. The location, size and shape of the ActiveSubpupil Region (ASR) 72 is continuously updated responsive to theeye-tracking subsystem 42, at a rate of update sufficient to accommodaterotations of the eye 20 by the user 22 so that the exit subpupils 32surrounding the eye pupil 38 are maintained in an active state. Similarto that illustrated in FIGS. 21 and 22, if the eye 22 of the user 22 isrotated for viewing in the first gaze direction 34.1 as illustrated inFIG. 22, the resulting associated Active Subpupil Region (ASR) 72determined by the subpupil modulation controller 50 is also concentricboth with the eye pupil 38 and with the optical axis 36, but with arelatively smaller diameter—relative to that associated with thefirst-aspect subpupil modulation scheme 70, 70.1—that is sufficientlylarge to account for possible error in the determination of thelocation, size and/or shape of the eye pupil 38 by the eye-trackingsubsystem 42. Referring to FIGS. 25 and 26, for the eye 22 of the user22 rotated up and to the left as illustrated in FIG. 26, and as aresult, a detection by the eye-tracking subsystem 42 of anelliptically-shaped eye pupil 38 located up and to the left of theassociated optical axis 36, in accordance with the second-aspectsubpupil modulation scheme 70, 70.2, the associated Active SubpupilRegion (ASR) 72 determined by the subpupil modulation controller 50 iscentered about the offset eye pupil 38, but elliptically shaped, similarthat of the eye pupil 38, wherein, as illustrated in FIG. 25, thelight-source elements 100, 100′, 100″ and associated modulated subpupils32′ within the Active Subpupil Region (ASR) 72 are activated by thesubpupil modulator 30, 30.2, 30.3, and the remaining modulated subpupils32′ intersecting or outside of the boundary of the Active SubpupilRegion (ASR) 72 are deactivated, resulting in the image 16 beingpresented to the eye 20 via only the activated exit subpupils 32 thatare associated with the activated modulated subpupils 32′ that arealigned with the eye pupil 38, as illustrated in FIG. 26. Accordingly,as a result of the Active Subpupil Region (ASR) 72 being dynamicallysized and shaped responsive to the size and shape of the eye pupil 38 asdetermined by the eye-tracking subsystem 42, the size and shape of theActive Subpupil Region (ASR) 72 can more closely match that of the eyepupil 38 while still mitigating against uneven vignetting by the edge ofthe eye pupil 38, which—in comparison with the first-aspect subpupilmodulation scheme 70, 70.1—results in a relatively lesser amount ofillumination of the portion of the eye 20 surrounding the eye pupil 38with extraneous light 16 ^(iv) that is then reflected or scattered bythe front surface 20′ of the eye 20 rather than being imaged onto theretina 24, and thereby also provides a benefit from a substantialreduction in electrical power consumption compared with that required bythe first aspect near-eye display system 10, 10.1 to power the entireflat-panel two-dimensional image-display array 52 of light-emittingimage-display pixels 54; and, to a lesser extent, compared with that ofthe first-aspect subpupil modulation scheme 70, 70.1, although to alesser extent.

The first- and second-aspect subpupil modulation schemes 70, 70.1, 70.2,supra, may each be configured to dynamically adapt the size and/or shapeof the Active Subpupil Region (ASR) 72 to that of the eye pupil 38, soas to provide for reducing the amount of extraneous light 16 ^(iv)reflected or scattered by the front surface 20′ of the eye 20, or, inthe case of the second—or third-aspect near-eye display systems 10,10.2, 10.2′, 10.3, 10.3′, so as to provide for further reducing theassociated amount of electrical power consumption. The diameter of theeye pupil 38 is controlled by the iris 40 of the eye 20 within a typicalrange of 2 millimeters to 8 millimeters, depending upon, and responsiveto, changes in the brightness of the image 16, wherein therelatively-smallest diameter of the eye pupil 38 results from therelatively-highest perceived intensity of the image 16, which, inrespect of the second—or third-aspect near-eye display systems 10, 10.2,10.2′, 10.3, 10.3′, provides the greatest opportunity for power savingsif the Active Subpupil Region (ASR) 72 diameter is reduced responsive todetection by the eye-tracking subsystem 42 of the size and/or shape ofthe eye pupil 38.

In accordance with the third aspect 70.3 of the subpupil modulationscheme 70, 70.3, rather than making the Active Subpupil Region (ASR) 72so large as to avoid a spatial transition of the edge of the eye pupil38 from an active to an inactive exit subpupil 32, instead, the ActiveSubpupil Region (ASR) 72 is constrained to a size that is smaller thanthat of the eye pupil 38, and is aligned with the center of the eyepupil 38, so as to prevent vignetting that could otherwise result from aspatial transition straddling edge of the eye pupil 38. Accordingly, thethird-aspect subpupil modulation scheme 70, 70.3 substantiallyeliminates the illumination of the portion of the eye 20 surrounding theeye pupil 38 with extraneous light 16 ^(iv) that would otherwise bereflected or scattered by the front surface 20′ of the eye 20 ratherthan being imaged onto the retina 24. Furthermore, a relatively smallerActive Subpupil Region (ASR) 72 provides for improving the perceivedquality of the image 16 by decreasing the effective aperture sizethrough which the light 16′ passes into the eye 20, thereby decreasingthe impact of aperture-size-related optical aberrations, which increasesclarity of the image 16, which is particularly effective in a near-eyedisplay system 10, 10.2, 10.2′, 10.3, 10.3′ that provides for arelatively-large field-of-view together with relatively-highmagnification. Referring to FIGS. 27 through 29, based upon an estimatefrom the eye-tracking subsystem 42 of the location of the center of theeye pupil 38, the subpupil modulation controller 50 identifies andactivates the modulated subpupil 32′—i.e. the associated light-sourceelement 100, 100′, 100″— of an associated Active Subpupil Region (ASR)72, associated with the exit subpupil 32 that is most-closely alignedwith the eye pupil 38, and deactivates the remaining modulated subpupils32′/light-source elements 100, 100′, 100″ of the subpupil modulator 30,30.2, 30.3/flat-panel 98 or curved 106 two-dimensional light-sourcearray. The location of the Active Subpupil Region (ASR) 72 iscontinuously updated responsive to the eye-tracking subsystem 42, at arate of update sufficient to accommodate rotations of the eye 20 by theuser 22, so that the exit subpupils 32 having corresponding one or moreprojected transverse locations so as to be located entirely withintransverse projection of the eye pupil 38, are maintained in an activestate. Referring to FIGS. 26 and 28, for the eye 22 of the user 22rotated for viewing in the first gaze direction 34.1 as illustrated inFIG. 28, and as a result, a detection by the eye-tracking subsystem 42of the eye pupil 38 being centered on the optical axis 36, theassociated Active Subpupil Region (ASR) 72 determined by the subpupilmodulation controller 50 is concentric both with the eye pupil 38 andwith the optical axis 36, and, in one set of embodiments, limited insize so as to encompass a corresponding single exit subpupil 32,wherein, as illustrated in FIG. 27, the light-source element 100, 100′,100″ and associated modulated subpupil 32′ within the Active SubpupilRegion (ASR) 72 is activated by the subpupil modulator 30, 30.2, 30.3,and the remaining modulated subpupils 32′ outside the boundary of theActive Subpupil Region (ASR) 72 are deactivated, resulting in the image16 being presented to the eye 20 via only the activated exit subpupil 32associated with the activated modulated subpupil 32′, as illustrated inFIG. 28, and thereby also provides a benefit from a substantialreduction in electrical power consumption compared with that required bythe first aspect near-eye display system 10, 10.1 to power the entireflat-panel two-dimensional image-display array 52 of light-emittingimage-display pixels 54, and, to a lesser extent, compared with that ofthe first- and second-aspect subpupil modulation schemes 70, 70.1, 70.2.Referring to FIGS. 29 and 30, for the eye 22 of the user 22 rotated upand to the left as illustrated in FIG. 30, and as a result, a detectionby the eye-tracking subsystem 42 of an elliptically-shaped eye pupil 38located up and to the left of the associated optical axis 36, inaccordance with the third-aspect subpupil modulation scheme 70, 70.3,the associated Active Subpupil Region (ASR) 72 determined by thesubpupil modulation controller 50 is located—for example,centered—within the offset eye pupil 38, wherein, as illustrated in FIG.29, the light-source element 100, 100′, 100″ and associated modulatedsubpupil 32′ within the Active Subpupil Region (ASR) 72 is activated bythe subpupil modulator 30, 30.2, 30.3, and the remaining modulatedsubpupils 32′ outside the boundary of the Active Subpupil Region (ASR)72 are deactivated, resulting in the image 16 being presented to the eye20 via only the activated exit subpupil 32 associated with the activatedmodulated subpupil 32′, as illustrated in FIG. 30, and thereby alsoprovides a benefit from a substantial reduction in electrical powerconsumption compared with that required by the first aspect near-eyedisplay system 10, 10.1 to power the entire flat-panel two-dimensionalimage-display array 52 of light-emitting image-display pixels 54, and,to a lesser extent, compared with that of the first- and second-aspectsubpupil modulation schemes 70, 70.1, 70.2.

The subpupil modulation schemes 70, 70.1, 70.2, 70.3 may be adapted toaccommodate errors—by the eye-tracking subsystem 42—in estimates of theposition and/or size of the eye pupil 38, or errors in the position ofthe eye pupil 38 relative to the associated subpupil surface 84 andassociated one or more exit subpupils 32, for example, which may resultfrom a lag in the detection and determination of those parameters, or alag in the implementation by the subpupil modulation controller 50 ofchanges to the Active Subpupil Region (ASR) 72 responsive to thoseparameters. For example, these errors may occur, or be accentuated, as aresult of either rapid eye movement or a mechanical misalignment of thenear-eye display system 10, 10.1, 10.2, 10.2′, 10.3, 10.3′ relative tothe eye 20, for example, as a result of manual adjustment or a physicalbumping that may be optionally reported to the subpupil modulationcontroller 50 by an optional accelerometer incorporated in the near-eyedisplay system 10, 10.1, 10.2, 10.2′, 10.3, 10.3′. For example,responsive to the detection of a condition—for example, rapid eyemovement or a physical bumping of the near-eye display system 10, 10.1,10.2, 10.2′, 10.3, 10.3′—associated with prospective eye-trackingerrors, the subpupil modulation controller 50 can provide for increasingthe size of the Active Subpupil Region (ASR) 72 to accommodate theassociated uncertainty in the location of the eye pupil 38 relative tothe associated exit subpupil surface 84 and associated one or more exitsubpupils 32. Accordingly, the size, shape and location of the ActiveSubpupil Region (ASR) 72 implemented by the subpupil modulation schemes70, 70.1, 70.2, 70.3 can be dynamically modified during such events tocompensate for such temporary prospective errors, and then later reducedin size to either, or both, reduce the reflection or scatteringextraneous light 16 ^(iv), or reduce electrical power consumption, afterthe situation has stabilized.

The first- and second-aspect subpupil modulators 30, 30.2, 30.3, supra,each generate an associated array of discrete, spatially adjacent exitsubpupils 32 on a subpupil surface 84, where each exit subpupil 32 is animage of an associated corresponding modulation element 90 within acorresponding array of modulation elements 90, the physicalimplementation of which typically includes boundary regions betweenadjacent modulation elements 90 that, for example, incorporate, orprovide for, associated electronic circuitry, the edges of a lightpipes, or other structures that result in a physically discontinuousmodulation surface 92, and a resulting similarly discontinuous array ofcorresponding associated exit subpupils 32 at the subpupil surface 84,which causes, within the subpupil surface 84, a grid-like pattern ofdarkness between active exit subpupils 32.

For a subpupil surface 84 that does not conform to the concave geometricsurface construct 82, 82′, supra, the effect of this grid-like patternson the uniform perceived brightness of the composite image 88 increaseswith axial separation of the eye pupil 38 from the associated exitsubpupil 32 as a result of a rotation of the eye 20. This effect can besomewhat mitigated by blurring the image of adjacent exit subpupils32—for example, by increasing the sizes thereof, —or by implementingother means of reducing spatial structures in the image of the exitsubpupils 32, however, a relative increase in the size of the exitsubpupil 32 may not otherwise be desirable. The fixed spatialorganization of the array of exit subpupils 32 resulting from the fixedspatial organization of the corresponding array of modulation elements90 results in a corresponding relatively-fixed location of anyindividual exit subpupil 32 on the subpupil surface 84.

Referring to FIGS. 31-43, the fourth aspect 10.4 of the near-eye displaysystem 10, 10.4, and an associated first embodiment 10.4′ thereof, issubstantially the same as the third-aspect near-eye display system 10,10.3, 10.3′, supra, except that an associated fourth-aspect imagegenerator 12, 12.4 incorporates a controllable light source 97 thatincorporates a curved light-redirecting surface 110 in cooperation witha modulated scanned beam of light that is generated by scanning—in twodimensions—a beam of light 114 with a light-beam scanner 116 to generatethe light 104 to illuminate the associated flat-panel two-dimensionalimage-display modulation array 94 of light-modulating image-displaypixels 96, for example, the latter of which is illustrated in FIG. 33,which also provides for an associated curved modulation surface 92, 92″,but without utilizing a set of individual light-source elements 100,100′, 100″ of the curved two-dimensional light-source array 106. Themodulated scanned beam of light 112 is generated by anintensity-modulatable light-beam source 118 that illuminates alight-beam-directing element 120—for example, and electro-mechanicallyactuated mirror, holographic element, or a diffractive element—of thelight-beam scanner 116, wherein the light-beam source 118, and thelight-beam scanner 116 are each operatively coupled to, and undercontrol of, the subpupil modulation controller 50 that provides forcontrolling the activation and intensity of the light-beam source 118responsive to a light-beam-magnitude subpupil modulation control signal51′, and that provides for controlling the location of the modulatedscanned beam of light 112 on the curved light-redirecting surface 110responsive to a light-beam-position subpupil modulation control signal51″, so as to collectively provide for both temporal and angularmodulation of the modulated scanned beam of light 112, respectively.Accordingly, the modulated scanned beam of light 112 in cooperation withthe curved light-redirecting surface 110—including the underlyinglight-beam source 118 and light-beam scanner 116 under control of thesubpupil modulation controller 50—constitute a fourth-aspect subpupilmodulator 30, 30.4 associated with the fourth aspect near-eye displaysystem 10, 10.4, 10.4′, with the underlying curved light-redirectingsurface 110 constituting an associated curved modulation surface 92,92″. The same as for the third-aspect near-eye display system 10, 10.3,10.3′, with the subpupil surface 84 being an image of the modulationsurface 92, this results in a corresponding associated concave-curvedsubpupil surface 84, 84″ that conforms to the concave geometric surfaceconstruct 82, 82′ (illustrated in FIG. 9) defined by the front surface20′ of the eye 20 over a range of rotations, which provides forminimizing the variation in axial distance between the eye pupil 38 andany active exit subpupil 32 over a range of possible rotations of theeye 20.

The region 122 of the curved light-redirecting surface 110 over whichthe modulated scanned beam of light 112 is scanned constitutes—in thecontext of the fourth-aspect near-eye display system 10, 10.3, 10.3′—aneffective light source 124 that can be continuous over an arbitraryshape, of an arbitrary size, at an arbitrary location, and with anarbitrary intensity profile, and which is associated with acorresponding single modulated subpupil 32′, wherein the light 104redirected from the curved light-redirecting surface 110 is transformedby the conditioner lens 102, 102′, L₁ into a corresponding beam 64′ oflight 16′ that propagates in a direction that is responsive to thelocation of the region 122 on the curved light-redirecting surface 110from which the light 104 originates, in association with a correspondingsingle exit subpupil 32. The curved light-redirecting surface 110provides for redirecting and redistributing—for example, by scatteringor diffraction, or a combination thereof—the light 104 of the modulatedscanned beam of light 112 with a sufficient diversity of scatteringangles therefrom so as to provide for illuminating the entirety of theflat-panel two-dimensional image-display modulation array 94 from everylocation on the curved light-redirecting surface 110 that can beassociated with an associated modulated subpupil 32′ and the exitsubpupil 32, while also providing for forming an image of the associatedeffective light source 124 on the concave-curved subpupil surface 84,84″ as an associated curved subpupil image 126.

At any given time, when actuated, the beam of light 114 from thelight-beam source as directed by the light-beam-directing element 120 ofthe light-beam scanner 116 inherently forms a light spot 104′ within theregion 122 of the curved light-redirecting surface 110, which may besteered to any location on the curved light-redirecting surface 110responsive to angular modulation of the light-beam scanner 116. Theultimate shape and size of the resulting effective light source 124 areprovided for by rapidly angularly modulating or “scanning” the lightspot 104′ along an associated path within the region 122 of the curvedlight-redirecting surface 110 corresponding to the associated ActiveSubpupil Region (ASR) 72, wherein, as a result of persistence of the eye20, the rapid and repetitive scanning of the light spot 104′ along theassociated path—similar to the working of a vector-based graphicaldisplay—gives the appearance of a relatively continuously filledeffective light source 124. In one set of embodiments, either thelight-beam source 118, or of the associated beam of light 114, may beintensity modulated during the scanning process to provide forcontrolling the resulting intensity, or the associated intensityprofile, of the effective light source 124.

Notwithstanding that the light-beam scanner 116 and light-beam-directingelement are illustrated in FIGS. 31 and 32 at an off-axis locationrelative to the optical axis 36 of the associated optical subsystem 14,14.2 so as to not obstruct the illumination of the flat-paneltwo-dimensional image-display modulation array 94 from the curvedlight-redirecting surface 110, alternatively, the light-beam scanner 116and light-beam-directing element 120 could be used in cooperation with abeam splitter to provide for on-axis illumination of the curvedlight-redirecting surface 110.

Referring also to FIG. 32, in accordance with one set of embodiments,the relatively outboard region of the curved light-redirecting surface110 is located one focal length f₁ from the associated firstdioptric-power optical element 56, 56.1, 56.1′, L₁/conditioner lens 102,102′, L₁. The second dioptric-power optical element 56, 56.2, 56.2′, L₂in cooperation with the conditioner lens 102, 102′, L₁ provide forforming the curved subpupil image 126 of both the subpupil modulator 30,30.4/curved light-redirecting surface 110 and the associated aperturestop 28, at the exit pupil 18 located proximate to the front surface 20′of the eye 20 and associated with the corresponding concave-curvedsubpupil surface 84, 84″. For example, the curved light-redirectingsurface 110 may comprise, but is not limited to, a light-scatteringsurface, a holographic surface, a diffractive surface, or a combinationthereof.

The light 104 originating from the region 122 of the curvedlight-redirecting surface 110 is controlled by the subpupil modulationcontroller 50 responsive to the eye-tracking subsystem 42, dependingupon the associated subpupil modulation scheme 70. In comparison withthe first-, second—and third-aspect near-eye display systems 10, 10.1,10.2, 10.2′, 10.3, 10.3′, the fourth aspect near-eye display system 10,10.4, 10.4′ provides for more precisely positioning and sizing anassociated single exit subpupil 32 that forms the associated compositeimage 88, without the presence of a grid-like pattern of darkness withinthe associated curved subpupil image 126.

Referring to FIGS. 34-42, the fourth-aspect subpupil modulator 30, 30.4is controlled by the subpupil modulation controller 50 in accordancewith a subpupil modulation scheme 70 that provides for identifying anActive Subpupil Region (ASR) 72 of the subpupil modulator 30, 30.4responsive to the location, size, and possibly the shape, of the eyepupil 38 as determined by the eye-tracking subsystem 42, and thatprovides for scanning the region 122 of the curved light-redirectingsurface 110 so as to form the effective light source 124 associated witha corresponding modulated subpupil 32′ within the Active Subpupil Region(ASR) 72 so as to generate light 104 therefrom; and for not illuminatingthe remaining portion of the curved light-redirecting surface 110 withthe modulated scanned beam of light 112 so as to not generate light 104therefrom. In comparison with the first-aspect near-eye display system10, 10.1, for which the powering of the light-emitting image-displaypixels 54 of the entire flat-panel two-dimensional image-display array52 is independent of which exit subpupils 32 are activated, and incomparison with the second—and third-aspect near-eye display systems 10,10.2, 10.2′, 10.3, 10.3′, for which a light-source element 100 isilluminated in association with each active exit subpupil 32, inaccordance with the fourth aspect near-eye display system 10, 10.4,10.4′, only the light-beam source 118 and light-beam scanner 116 arepowered, and the associated flat-panel two-dimensional image-displaymodulation array 94 consumes only a negligible amount of power, whichtherefor provides a substantial reduction in power consumption relativeto that of the first-aspect, and possibly also the second—andthird-aspect, near-eye display systems 10, 10.1, 10.2, 10.2′, 10.3,10.3′.

Referring to FIGS. 34-37, in accordance with the first aspect 70.1 ofthe subpupil modulation scheme 70, 70.1, the Active Subpupil Region(ASR) 72 is set to a fixed size and shape that is sufficiently large tosurround the eye pupil 38 regardless of the orientation of the eye 20,and regardless of the associated state of the iris 40, withaccommodation for the largest anticipated lateral extent of the eyepupil 38 and accommodation of possible error in the determination of thelocation, size and/or shape of the eye pupil 38 by the eye-trackingsubsystem 42, so as to mitigate against a potential uneven vignetting byan edge of the eye pupil 38 that might otherwise result if the edge ofthe eye pupil 38 were to not be fully illuminated by an associated exitsubpupil 32, for example, as might otherwise result from a misalignmentbetween the eye pupil 38 and the Active Subpupil Region (ASR) 72 thatcould otherwise cause a spatial transition of the edge of the eye pupil38 from an active subpupil 32 inside the Active Subpupil Region (ASR) 72to an inactive subpupil 32 outside the Active Subpupil Region (ASR) 72as a result of relative motion between the eye pupil 38 and the ActiveSubpupil Region (ASR) 72. The location of the Active Subpupil Region(ASR) 72 is continuously updated responsive to the eye-trackingsubsystem 42, at a rate of update sufficient to accommodate rotations ofthe eye 20 by the user 22 so as to provide for the active-state exitsubpupil 32 to continuously surround the eye pupil 38. Referring toFIGS. 34 and 35, for the eye 22 of the user 22 rotated for viewing inthe first gaze direction 34.1 as illustrated in FIG. 35, and as aresult, a detection by the eye-tracking subsystem 42 of the eye pupil 38being centered on the optical axis 36, the associated Active SubpupilRegion (ASR) 72 determined by the subpupil modulation controller 50 isconcentric both with the eye pupil 38 and with the optical axis 36, witha diameter sufficiently greater than that of the eye pupil 38 so thatthe eye pupil 38 will be fully illuminated by the active-state exitsubpupil 32, wherein, as illustrated in FIG. 34, the modulated scannedbeam of light 112 of the associated subpupil modulator 30, 30.4 isscanned so as to form—in the region 122 of the curved light-redirectingsurface 110—an effective light source 124 and associated modulatedsubpupil 32′ that spans the Active Subpupil Region (ASR) 72; and aremaining portion of the curved light-redirecting surface 110 is notilluminated, so as to present the image 16 to the eye 20 via a singleexit subpupil 32 that fills the associated Active Subpupil Region (ASR)72, as illustrated in FIG. 35. Referring to FIGS. 36 and 37, for the eye22 of the user 22 rotated up and to the left as illustrated in FIG. 37,and as a result, a detection by the eye-tracking subsystem 42 of anelliptically-shaped eye pupil 38 located up and to the left of theassociated optical axis 36, in accordance with the first-aspect subpupilmodulation scheme 70, 70.1, the associated Active Subpupil Region (ASR)72 determined by the subpupil modulation controller 50 is centered aboutthe offset eye pupil 38, but with the same diameter as illustrated inFIGS. 34 and 35, wherein, as illustrated in FIG. 36, the modulatedscanned beam of light 112 of the associated subpupil modulator 30, 30.4is scanned so as to form—in the region 122 of the curvedlight-redirecting surface 110—an effective light source 124 andassociated modulated subpupil 32′ that spans the Active Subpupil Region(ASR) 72; and a remaining portion of the curved light-redirectingsurface 110 is not illuminated, so as to present the image 16 to the eye20 via a single exit subpupil 32 that fills the associated ActiveSubpupil Region (ASR) 72 that is aligned with the eye pupil 38, asillustrated in FIG. 37. Accordingly, notwithstanding the resultingmitigation against uneven vignetting by the eye pupil 38, thefirst-aspect subpupil modulation scheme 70, 70.1 results in theillumination of a portion of the eye 20 surrounding the eye pupil 38with extraneous light 16 ^(iv) that is then reflected, or scattered, bythe front surface 20′ of the eye 20 rather than being imaged onto theretina 24, and thereby also provides a benefit from a substantialreduction in electrical power consumption compared with that required bythe first aspect near-eye display system 10, 10.1 to power the entireflat-panel two-dimensional image-display array 52 of light-emittingimage-display pixels 54,

Referring to FIGS. 38 and 39, in accordance with the second aspect 70.2of the subpupil modulation scheme 70, 70.2, the Active Subpupil Region(ASR) 72 is set to a variable size and shape that is adapted to besufficiently large surround the eye pupil 38 regardless of theorientation of the eye 20, and regardless of the associated state of theiris 40, which—the same as for the first-aspect subpupil modulationscheme 70, 70.1, but accompanied by a lesser amount of extraneous light16 ^(iv)—also provides for mitigating against a potential unevenvignetting by an edge of the eye pupil 38 that might otherwise result ifthe edge of the eye pupil 38 were to not be fully illuminated by anassociated exit subpupil 32. The location, size and shape of the ActiveSubpupil Region (ASR) 72 is continuously updated responsive to theeye-tracking subsystem 42, at a rate of update sufficient to accommodaterotations of the eye 20 by the user 22 so as to provide for theactive-state exit subpupil 32 to continuously surround the eye pupil 38.Similar to that illustrated in FIGS. 34 and 35, if the eye 22 of theuser 22 is rotated for viewing in the first gaze direction 34.1 asillustrated in FIG. 35, the resulting associated Active Subpupil Region(ASR) 72 determined by the subpupil modulation controller 50 is alsoconcentric both with the eye pupil 38 and with the optical axis 36, butwith a relatively smaller diameter—relative to that associated with thefirst-aspect subpupil modulation scheme 70, 70.1—that is sufficientlylarge to account for possible error in the determination of thelocation, size and/or shape of the eye pupil 38 by the eye-trackingsubsystem 42. Referring to FIGS. 38 and 39, for the eye 22 of the user22 rotated up and to the left as illustrated in FIG. 39, and as aresult, a detection by the eye-tracking subsystem 42 of anelliptically-shaped eye pupil 38 located up and to the left of theassociated optical axis 36, in accordance with the second-aspectsubpupil modulation scheme 70, 70.2, the associated Active SubpupilRegion (ASR) 72 determined by the subpupil modulation controller 50 iscentered about the offset eye pupil 38, but elliptically shaped, similarthat of the eye pupil 38, wherein, as illustrated in FIG. 38, themodulated scanned beam of light 112 of the associated subpupil modulator30, 30.4 is scanned so as to form—in the region 122 of the curvedlight-redirecting surface 110—an effective light source 124 andassociated modulated subpupil 32′ that spans the Active Subpupil Region(ASR) 72; and a remaining portion of the curved light-redirectingsurface 110 is not illuminated, so as to present the image 16 to the eye20 via a single exit subpupil 32 that fills the associated ActiveSubpupil Region (ASR) 72 that is aligned with the eye pupil 38, asillustrated in FIG. 39. Accordingly, as a result of the Active SubpupilRegion (ASR) 72 being dynamically sized and shaped responsive to thesize and shape of the eye pupil 38 as determined by the eye-trackingsubsystem 42, the size and shape of the Active Subpupil Region (ASR) 72can more closely match that of the eye pupil 38 while still mitigatingagainst uneven vignetting by the edge of the eye pupil 38, which—incomparison with the first-aspect subpupil modulation scheme 70,70.1—results in a relatively lesser amount of illumination of theportion of the eye 20 surrounding the eye pupil 38 with extraneous light16 ^(iv) that is then reflected or scattered by the front surface 20′ ofthe eye 20 rather than being imaged onto the retina 24, and thereby alsoprovides a benefit from a substantial reduction in electrical powerconsumption compared with that required by the first aspect near-eyedisplay system 10, 10.1 to power the entire flat-panel two-dimensionalimage-display array 52 of light-emitting image-display pixels 54, and,to a lesser extent, compared with that of the first-aspect subpupilmodulation scheme 70, 70.1.

The first- and second-aspect subpupil modulation schemes 70, 70.1, 70.2,supra, may each be configured to dynamically adapt the size and/or shapeof the Active Subpupil Region (ASR) 72 to that of the eye pupil 38, soas to provide for reducing the amount of extraneous light 16 ^(iv)reflected or scattered by the front surface 20′ of the eye 20. Thediameter of the eye pupil 38 is controlled by the iris 40 of the eye 20within the typical range of 2 millimeters to 8 millimeters, dependingupon, and responsive to, changes in the brightness of the image 16,wherein the relatively-smallest diameter of the eye pupil 38 resultsfrom the relatively-highest perceived intensity of the image 16.

In accordance with the third aspect 70.3 of the subpupil modulationscheme 70, 70.3, rather than making the Active Subpupil Region (ASR) 72so large as to avoid a spatial transition of the edge of the eye pupil38 from an active to an inactive exit subpupil 32, instead the ActiveSubpupil Region (ASR) 72 is constrained to a size that is smaller thanthat of the eye pupil 38 and aligned with the center of the eye pupil 38so as to prevent vignetting that could otherwise result with thepresence of such a spatial transition. Accordingly, the third-aspectsubpupil modulation scheme 70, 70.3 substantially eliminates theillumination of the portion of the eye 20 surrounding the eye pupil 38with extraneous light 16 ^(iv) that would otherwise be reflected orscattered by the front surface 20′ of the eye 20 rather than beingimaged onto the retina 24. Furthermore, a relatively smaller ActiveSubpupil Region (ASR) 72 provides for improving the perceived quality ofthe image 16 by decreasing the effective aperture size through which thelight 16′ passes into the eye 20, thereby decreasing the impact ofaperture-size-related optical aberrations, which increases clarity ofthe image 16, and which is particularly effective in a near-eye displaysystem 10, 10.2, 10.2′, 10.3, 10.3′, 10.4, 10.4′ that provides for alarge field-of-view together with relatively high magnification.Referring to FIGS. 40 through 43, based upon an estimate from theeye-tracking subsystem 42 of the location of the center of the eye pupil38, the subpupil modulation controller 50 identifies an associatedActive Subpupil Region (ASR) 72 that is aligned with the eye pupil 38,and the modulated scanned beam of light 112 of the associated subpupilmodulator 30, 30.4 is scanned so as to form—in the region 122 of thecurved light-redirecting surface 110—an effective light source 124 andassociated modulated subpupil 32′ that spans the Active Subpupil Region(ASR) 72; wherein a remaining portion of the curved light-redirectingsurface 110 is not illuminated, so as to present the image 16 to the eye20 via a single exit subpupil 32 that fills the associated ActiveSubpupil Region (ASR) 72 that is aligned with the eye pupil 38. Thelocation of the Active Subpupil Region (ASR) 72 is continuously updatedresponsive to the eye-tracking subsystem 42, at a rate of updatesufficient to accommodate rotations of the eye 20 by the user 22 so thatthe associated active-state exit subpupil 32 is maintained within theeye pupil 38. Referring to FIGS. 40 and 41, for the eye 22 of the user22 rotated for viewing in the first gaze direction 34.1 as illustratedin FIG. 41, and as a result, a detection by the eye-tracking subsystem42 of the eye pupil 38 being centered on the optical axis 36, theassociated Active Subpupil Region (ASR) 72 determined by the subpupilmodulation controller 50 is concentric both with the eye pupil 38 andwith the optical axis 36, and limited in size so as to not overlap anedge of the eye pupil 38, wherein, as illustrated in FIG. 40, themodulated scanned beam of light 112 of the associated subpupil modulator30, 30.4 is scanned so as to form—in the region 122 of the curvedlight-redirecting surface 110—an effective light source 124 andassociated modulated subpupil 32′ that spans the associated ActiveSubpupil Region (ASR) 72; and a remaining portion of the curvedlight-redirecting surface 110 is not illuminated, so as to present theimage 16 to the eye 20 via a single exit subpupil 32 that fills theassociated Active Subpupil Region (ASR) 72 that is aligned with, butsmaller than, the eye pupil 38, as illustrated in FIG. 41, and therebyalso provides a benefit from a substantial reduction in electrical powerconsumption compared with that required by the first aspect near-eyedisplay system 10, 10.1 to power the entire flat-panel two-dimensionalimage-display array 52 of light-emitting image-display pixels 54, and,to a lesser extent, compared with that of the first- and second-aspectsubpupil modulation schemes 70, 70.1, 70.2. Referring to FIGS. 42 and43, for the eye 22 of the user 22 rotated up and to the left asillustrated in FIG. 43, and as a result, a detection by the eye-trackingsubsystem 42 of an elliptically-shaped eye pupil 38 located up and tothe left of the associated optical axis 36, in accordance with thethird-aspect subpupil modulation scheme 70, 70.3, the associated ActiveSubpupil Region (ASR) 72 determined by the subpupil modulationcontroller 50 is located—for example, centered—within the offset eyepupil 38, wherein, as illustrated in FIG. 42, the modulated scanned beamof light 112 of the associated subpupil modulator 30, 30.4 is scanned soas to form—in the region 122 of the curved light-redirecting surface110—an effective light source 124 and associated modulated subpupil 32′that spans the Active Subpupil Region (ASR) 72; wherein a remainingportion of the curved light-redirecting surface 110 is not illuminated,so as to present the image 16 to the eye 20 via a single exit subpupil32 that fills the associated Active Subpupil Region (ASR) 72 that isaligned with, but smaller than, the eye pupil 38, as illustrated in FIG.43, and thereby also provides a benefit from a substantial reduction inelectrical power consumption compared with that required by the firstaspect near-eye display system 10, 10.1 to power the entire flat-paneltwo-dimensional image-display array 52 of light-emitting image-displaypixels 54, and, to a lesser extent, compared with that of the first- andsecond-aspect subpupil modulation schemes 70, 70.1, 70.2.

Referring to FIGS. 44-46, in accordance with a second embodiment 14.2″,the second-aspect optical subsystem 14, 14.2″ of each of thesecond-aspect 10.2, 10.2′, third-aspect 10.3, 10.3′ and fourth-aspect10.4, 10.4′ near-eye display systems 10, respectively, may bealternatively embodied with a free-form-surface/prism lens 56.2, L₂, 128providing for the associated second dioptric-power optical element 56,56.2, L₂. For example, free-form-surface/prism lenses are described thefollowing technical papers, which are incorporated herein by referencein their entirety: Dewen CHENG, Yongian WANG, Hong HUA and M. M. TALHA,“Design of an optical see-trough head-mounted display with a lowf-number and large field of view using a freeform prism”, APPLIEDOPTICS, Optical Society of America, Vol. 48, No. 14, 10 May 2009, pp.2655-2668; and Hong HUA, “Sunglass-like displays become a reality withfree-form optical technology”, 20 Aug. 2012, SPIE Digital Library, 2021,Internet download from:https://spie.org/news/4375-sunglass-like-displays-become-a-reality-with-free-form-optical-technology?SSO=1.

More particularly, referring to FIG. 44, a second embodiment 10.2″ of asecond-aspect near-eye display system 10, 10.2, 10.2″ incorporates thesame second-aspect image generator 12, 12.2 as described hereinabove andillustrated in FIG. 17, which provides for generating a correspondingassociated beam 64 of light 16′ for each associated modulated subpupil32′. Referring to FIG. 45, a second embodiment 10.3″ of a third-aspectnear-eye display system 10, 10.3, 10.3″ incorporates the samethird-aspect image generator 12, 12.3 as described hereinabove andillustrated in FIG. 19, which also provides for generating acorresponding associated beam 64 of light 16′ for each associatedmodulated subpupil 32′. Referring to FIG. 46, a second embodiment 10.4″of a fourth-aspect near-eye display system 10, 10.4, 10.4″ incorporatesthe same fourth-aspect image generator 12, 12.4 as described hereinaboveand illustrated in FIG. 32, which also provides for generating acorresponding associated beam 64 of light 16′ for each associatedmodulated subpupil 32′. For each of the embodiments illustrated in FIGS.44-46, and for each associated modulated subpupil 32′, the correspondingassociated beam 64 of light 16′ enters a free-form refractive firstsurface 128.1 of the associated free-form-surface/prism lens 56.2, L₂,128, then reflects from a free-form second surface 128.2 due to totalinternal reflection, then reflects from a free-form third surface 128.3with a reflective coating, and finally exits the free-form-surface/prismlens 56.2, L₂, 128 through the free-form second surface 128.2 into theexit pupil 18 of the associated optical subsystem 14, 14.2″ for viewingof the associated virtual image 16′″ by the eye 20. Otherwise, each ofthe second-aspect 10.2, third-aspect 10.3 and fourth-aspect 10.4near-eye display systems function as described hereinabove inconjunction with FIGS. 16-17, 18-19 and 31-32, respectively.

In one set of embodiments, the infrared illuminator 44 and theinfrared-responsive camera 46 of the eye-tracking subsystem 42 arelocated proximate to the rear focal plane 62 of the second lens 56.2′,L₂ of the first aspect near-eye display system 10, 10.1, and proximateto the same plane as the flat-panel two-dimensional image-displaymodulation array 94 of the second 10.2, third 10.3 and fourth 10.4aspect near-eye display systems 10.

Generally, the subpupil surface 84, 84′, 84″ and accordingly, theassociated surface 18″ of the exit pupil 18, are located sufficientlyclose to, supra, the eye pupil 38 so that an activated exit subpupil 32can pass optical rays of the light 16′ of the image 16 into the eyepupil 38 so as to provide for viewing the entire image 16. The near-eyedisplay system 10, 10.2, 10.3, 10.4 provides for viewing the image 16 ata comfortable distance so that the associated virtual image 16′″ appearsto the either corrected (e.g. by eyeglasses or contact lenses) oruncorrected vision of the user 22 to be located at a distance from theuser 22 of between 2 meters and an infinity.

Each exit subpupil 32 is an image of its respective modulation element90 formed by the associated components of the associated opticalsubsystem 14, 14.1, 14.2, 14.2′, 14.2″. A simple-single-lens opticalimaging system typically forms an inverted image of the associatedobject. The first-aspect optical subsystem 14, 14.1 effectively acts astwo simple-single-lens optical imaging systems in tandem that providefor imaging the flat-panel two-dimensional image-display array 52,wherein a first of the two forms an intermediate, inverted image of theplane where the infrared illuminator 44 and the infrared-responsivecamera 46 of the eye-tracking subsystem 42 are located, and the secondof the two provides a virtual image 16′″ of that intermediate image,whereas the second-aspect optical subsystem 14, 14.2, 14.2′, 14.2″instead directly forms the virtual image of the virtual image 16′″ ofthe flat-panel two-dimensional image-display modulation array 94.Accordingly, the resulting virtual images 16′″ of the first aspect 14.1and second aspect 14.2, 14.2′, 14.2″ optical subsystems 14 arerelatively inverted with respect to one another, which is accommodatedby orienting the image 16 on the associated flat-panel two-dimensionalimage-display array 52 or flat-panel two-dimensional image-displaymodulation array 94 so that the image 16 appears to appear correctlyoriented to the user 22.

When incorporated as the second dioptric-power optical element 56, 56.2,L₂ of a near-eye display system 10, 10.2, 10.3, 10.4, thefree-form-surface/prism lens 56.2, L₂, 128 can provide for relativelylower cost, weight and design volume thereof so as to provide for arelatively more compact near-eye display system 10, 10.2, 10.3, 10.4,which can also be configured to combine the imagery from an associatedflat-panel two-dimensional image-display modulation array 94 with thatfrom the real environment of the user 22.

Referring to FIG. 47, a third embodiment 10.3′″ of a third aspect of anear-eye display system 10, 10.3, 10.3′″ incorporating a thirdembodiment 14.2′″ of the second-aspect optical subsystem 14, 14.2′″, issimilar to the first-embodiment third-aspect near-eye display system 10,10.3, 10.3′, supra, except that the second convergent magnifier lens56.2′, L₂ is replaced with a Fresnel magnifier lens 130, and theconditioner lens 102, 102′, L₁ is replaced with a Fresnel conditionerlens 132, wherein each of the Fresnel magnifier 130 and conditioner 132lenses incorporates at least one Fresnel surface 134, the latter ofwhich, for example, incorporates Fresnel structure 134′ incorporating aplurality of annular refractive segments, each incorporating a surfacecurvature similar to that of a conventional lens, but stepped relativeto the adjacent segment so as to reduce the overall thickness thereof tobeing that of the thickest refractive segment, resulting in acorresponding relatively-thin, macroscopically-flat structure that isrelatively-lighter weight than a corresponding conventional lens, andthat is relatively easier to package. If the Fresnel magnifier 130 andconditioner 132 lenses were illuminated over the entirety of theirsurfaces—some of which light is intended to enter the eye pupil 38, theremainder of which would otherwise illuminate the face of the user22—the Fresnel surfaces 134 thereof would tends to scatter a substantialamount of light from the discontinuities in the associated Fresnelstructures 134′, some of which scattered light would ultimately enterthe eye pupil 38 of the user 22 to cause a noticeable decrease inperceived image contrast. In view of the source of this scattered lightincluding both light 16′ through the associated optical subsystem 14that is intended to reach the eye pupil 38 as well as light 16′ thatwould unnecessarily reach other areas of the user's face, the use ofmodulated subpupils 32′, supra, provides for reducing the amount ofotherwise unnecessary light 16′, so as to therefore provide forimproving the perceived image contrast relative to that which wouldresult from a fully illuminated Fresnel magnifier 130 and conditioner132 lenses.

The third-embodiment third-aspect near-eye display system 10, 10.3,10.3′″ illustrated in FIG. 47 further incorporates two flat fold mirrors136—i.e. upper 136.1 and lower 136.2 fold mirrors 136, for example, eachat a 45 degree angle relative to the optical axis 36 aligned with theeye 20 of the user 22—that provide for folding the associated light pathbetween the subpupil modulator 30, 30.3 and the Fresnel magnifier lens130, so as to provide for a relatively-more compact physical assembly.It should be understood that any of the first—10.1, second—10.2, orthird—10.3 aspect near-eye display systems 10, supra, could incorporateone or more fold mirrors 136, 136.1, 136.2 so as to provide for arelatively-more compact physical assembly thereof, for which one or bothof the upper 136.1 and lower 136.2 fold mirrors 136 incorporated in thethird-embodiment third-aspect near-eye display system 10, 10.3, 10.3′″are otherwise optional.

Regardless of the particular aspect 10.1, 10.2, 10.3, 10.4 of thenear-eye display system 10, 10.1, 10.2, 10.3, 10.4, for purposes ofdetermining the prescriptions of the underlying dioptric-power opticalelements 56, 56.1, 56.2, 56.3, the action of the associated opticalsubsystem 14, 14.1, 14.2, 14.2′, 14.2″, 14.2′″ may be decomposed into:

a) the generation of the virtual image 16′″—as viewable by the user22—of either i) the flat-panel two-dimensional image-display array 52 ofthe first aspect near-eye display system 10, 10.1 by the first 56.1′,L₁, second 56.2′, L₂, and third 56.1′, L₃ convergent magnifier lensesthereof, or ii) the flat-panel two-dimensional image-display modulationarray 94 by the second convergent magnifier lens 56.2′, L₂ of thesecond—10.2, third—10.3 or fourth—10.4 aspect near-eye display system10, 10.2, 10.3, 10.4; and

b) the generation of the exit-pupil image 18′—i.e. a real image—ofeither i) the subpupil modulator 30, 30.1 by the second 56.2′, L₂ andthird 56.3′, L₃ convergent magnifier lenses of the first aspect near-eyedisplay system 10, 10.1, or ii) the subpupil modulator 30, 30.2, 30.3,30.4 by the conditioner lens 102, 102′, L₁ in cooperation with the ofthe second convergent magnifier lens 56.2′, L₂ of the second—10.2,third—10.3 or fourth—10.4 aspect near-eye display system 10, 10.2, 10.3,10.4.

More particularly, in respect of the second—10.2, third—10.3 orfourth—10.4 aspect near-eye display system 10, 10.2, 10.3, 10.4, inaccordance with one method, the prescription of the associated secondconvergent magnifier lens 56.2′, L₂ is first independently determined inthe context of a hypothetical embodiment 10.2′″ of a second-aspectnear-eye display system 10.2, 10.2′″ illustrated in FIG. 48 inaccordance with a magnifier-lens prescription design process 4900illustrated in FIG. 49, and then the prescription of the associated theassociated conditioner lens 102, 102′, L₁ is determined in the contextof the second—10.2, third—10.3 or fourth—10.4 aspect near-eye displaysystem 10, 10.2, 10.3, 10.4, in accordance with a conditioner-lensprescription design process 5000 illustrated in FIG. 50, with theconditioner lens 102, 102′, L₁ in cooperation with the second convergentmagnifier lens 56.2′, L₂ prescribed by the magnifier-lens prescriptiondesign process 4900, supra.

More particularly, referring to FIG. 48, for purposes ofillustration—but otherwise not limiting to a particular aspect of thenear-eye display system 10, 10.2, 10.3, 10.4—the hypothetical embodiment10.2′″ of the second-aspect near-eye display system 10.2, 10.2′″comprises a flat-panel two-dimensional image-display modulation array 94illustrated in cooperation with a Fresnel magnifier lens 56.2, L₂, 130.The flat-panel two-dimensional image-display modulation array 94 isilluminated by a flat-panel two-dimensional light-source array 98 (notillustrated), wherein in FIG. 48, six locations of a source image 16 onthe flat-panel two-dimensional image-display modulation array 94 areshown, with each being illuminated from three different directions,resulting in three light rays emanating from each of the six locations.Light 16′ from the flat-panel two-dimensional light-source array 98propagates through the Fresnel magnifier lens 56.2, L₂, 130 and onto anassociated planar exit pupil 18 at three corresponding locations thatare responsive to the direction of the corresponding light rays from thecorresponding six locations on the flat-panel two-dimensionalimage-display modulation array 94. Proximate surfaces of the Fresnelmagnifier lens 56.2, L₂, 130 are located at distances D_(P) from theexit pupil 18 and D_(D) from the flat-panel two-dimensionalimage-display modulation array 94, respectively, with the Fresnelmagnifier lens 56.2, L₂, 130 located therebetween. Accordingly, thethree light rays from each of six locations on the flat-paneltwo-dimensional image-display modulation array 94 are associated with acorresponding six light rays at each of three locations in the exitpupil 18 associated with a corresponding exit-pupil image 18′, thelatter of which is in turn associated with a virtual image 16′″ of theflat-panel two-dimensional image-display modulation array 94 located ata distance of Di from the exit pupil 18, responsive to the location ofthe Fresnel magnifier lens 56.2, L₂, 130, i.e. responsive to distancesD_(P) and D_(D), and to the focal length of the Fresnel magnifier lens56.2, L₂, 130.

Notwithstanding that in actuality, light 16′ associated with the virtualimage 16′″ propagates from the flat-panel two-dimensional image-displaymodulation array 94 (that displays an associate source image 16) to theexit pupil 18, the magnifier-lens prescription design process 4900instead follows the light 16′ in reverse from the virtual image 16′″ tothe exit pupil 18, then through the Fresnel magnifier lens 56.2, L₂, 130to the flat-panel two-dimensional image-display modulation array 94,thereby effectively treating the virtual image 16′″ as a design object138 being imaged by the hypothetical embodiment 10.2′″ of thesecond-aspect near-eye display system 10.2, 10.2′″, and effectivelytreating the associated resulting light distribution at the flat-paneltwo-dimensional image-display modulation array 94 as the design image140 of that design object 138. In optical design, an object and itsimage are conjugates of each other, supporting a design option ofselecting either as the “object” in the associated a design exercise. Byanalyzing the propagation of light in reverse from that which wouldoccur in the actual second-aspect near-eye display system 10.2, 10.2′″,the field of view and the size and location of the exit pupil 18 can bereadily established as fixed parameters in cooperation with the virtualimage 16′″ being treated as the design object 138, with the operationalexit pupil 18 therefore being treated instead as a design entrance pupil141, which provides for a relatively-more efficient prescription designprocess than if the locations of the design object 138 and the designimage 140 were reversed so as to be in correspondence with the causalityof the actual second-aspect near-eye display system 10.2, 10.2′″.

More particularly, referring to FIG. 49, in accordance with one set ofembodiments, and in the context of the hypothetical-embodimentsecond-aspect near-eye display system 10.2, 10.2′″, the magnifier-lensprescription design process 4900 commences in step (4902) with thedefinition of the following parameters of the hypothetical-embodimentsecond-aspect near-eye display system 10.2, 10.2′″: 1) the size andshape of the planar exit pupil 18, i.e. so as to be sufficient tooverlay a range of positions of the eye pupil 38 for a range of users22; 2) the horizontal field-of-view angle subtended in a horizontaldirection at the exit pupil 18 by the range of light rays associatedwith the virtual image 16′″; 3) the vertical field-of-view anglesubtended in a vertical direction at the exit pupil 18 by the range oflight rays associated with the virtual image 16′″; 4) the distance D_(P)between the exit pupil 18 and a proximate surface of the Fresnelmagnifier lens 56.2, L₂, 130; 5) the distance D_(D) between the Fresnelmagnifier lens 56.2, L₂, 130 and the flat-panel two-dimensionalimage-display modulation array 94; 6) the distance Di from the exitpupil 18 to the virtual image 16′″ of the flat-panel two-dimensionalimage-display modulation array 94; and 7) the thickness t of the Fresnelmagnifier lens 56.2, L₂, 130. For example, in one embodiment, a 20millimeter diameter circular exit pupil 18 (the design entrance pupil)is defined, through which pass the optical rays from a rectangularvirtual image 16′″ (the design object 138) positioned 2 meters (Di)forward of the exit pupil 18, the center of which virtual image 16′″ isaligned with the center of the exit pupil 18 along an associated opticalaxis 36, for which the virtual image 16′″ subtends a 76 degreehorizontal by 46 degree vertical field of view with respect to the exitpupil 18 and the associated optical axis 36, wherein the combination ofthe size of the exit pupil 18 and the associated field of view providefor a favorable viewing experience for the user 22. A 1.5 millimeterthick (t) Fresnel magnifier lens 56.2, L₂, 130 comprising a generallyflat optical acrylic substrate is positioned 22 millimeters forward(D_(P)) of the exit pupil 18 so as to provide sufficient space forcorrective glasses, and a flat flat-panel two-dimensional image-displaymodulation array 94 (the design image plane) is defined an additional 32millimeters (D_(D)) beyond the Fresnel magnifier lens 56.2, L₂, 130 soas to provide for a relatively compact assembly of an associatedthird-embodiment third-aspect near-eye display system 10, 10.3, 10.3′″.

The magnifier-lens prescription design process 4900 provides fordetermining the prescription of the Fresnel magnifier lens 56.2, L₂, 130that will provide for forming an optimal design image 140 of the virtualimage 16′″ at the location of the flat-panel two-dimensionalimage-display modulation array 94 based upon the assumption that thevirtual image 16′″ of the flat-panel two-dimensional image-displaymodulation array 94 formed by the Fresnel magnifier lens 56.2, L₂, 130will be similarly optimized, wherein as used herein, the term optimizedis associated with a configuration associated with an extremum (e.g.minimum) of an associated merit, or objective, function. Accordingly,following the definition in step (4902) of the parameters of thehypothetical-embodiment second-aspect near-eye display system 10.2,10.2′″, in step (4904), the operation of the hypothetical-embodimentsecond-aspect near-eye display system 10.2, 10.2′″ is simulated usingoptical design software, for example, Zemax optical design software, toas to provide for optimizing—in step (4906)—the optical parametersassociated with one or both surfaces of the Fresnel magnifier lens 56.2,L₂, 130, for example, under the constraint of limiting the one or bothsurfaces to vary only in second and higher order aspheric parameters(with the general radius and conic parameters being of minor concern),for example, with the optimization providing for minimizing an opticaldesign merit function given by the two-dimensional peak-to-valley spotsize of the design image 140 formed at multiple locations at theflat-panel two-dimensional image-display modulation array 94, generallyas a weighted sum of two-dimensional peak-to-valley spot sizes fromvarious different locations. In accordance with one set of embodiments,each of the different locations is weighted equally. For example, duringthe optical design simulation, a light distribution at the planarsubpupil surface 84, 84′ of the exit pupil 18 is back-propagated throughthe Fresnel magnifier lens 56.2, L₂, 130 being optimized, and then ontothe associated planar surface of the flat-panel two-dimensionalimage-display modulation array 94 so as to form a corresponding designimage 140, from which the associated optical design merit function isevaluated. In accordance with one set of embodiments, during theoptimization process, both distortion and lateral chromatic aberrationare ignored in favor of a subsequent reliance upon electronicpredistortion and electronic chromatic precorrection of the image 16 tobe displayed on the flat-panel two-dimensional image-display modulationarray 94 of the associated near-eye display system 10, 10.2, 10.2′,10.2″, 10.3, 10.3′, 10.3″, 10.3′″, 10.4, 10.4′, 10.4″.

Accordingly, the simulated propagation of optical rays from the designobject 138 (i.e. the virtual image 16′″) through the exit pupil 18acting as an entrance pupil for the simulation, then through the Fresnelmagnifier lens 56.2, L₂, 130, forms a simulated design image 140 at thelocation of the flat-panel two-dimensional image-display modulationarray 94, with rays generally converging appropriately at multiplerepresentative points as a design image 140 of the rectangular designobject 138. As a result of the optimization, the design image 140 at thelocation of the flat-panel two-dimensional image-display modulationarray 94 subtends a diagonal measurement of approximately 39millimeters. Accordingly, the use of a flat-panel two-dimensionalimage-display modulation array 94 of that diagonal measurement at thedistance D_(P), from the designed Fresnel magnifier lens 56.2, L₂, 130in the hypothetical-embodiment second-aspect near-eye display system10.2, 10.2′″ will provide for a virtual image 16′″ having a diagonalfield of view similar to the diagonal field of view associated with the76 degree horizontal by 46 degree vertical field of view designparameters, subject to the impact of geometric distortion.

In respect of the determination, or optimization, of the prescription ofthe first 56.1′, L₁, second 56.2′, L₂, and third 56.1′, L₃ convergentmagnifier lenses of the first-aspect near-eye display system 10, 10.1,the magnifier-lens prescription design process 4900 can besimultaneously applied to all three convergent magnifier lenses 56.1′,L₁; 56.2′, L₂; third 56.3′, L₃ that act collectively as a magnifier lensof the first-aspect near-eye display system 10, 10.1, by searching withrespect to a composite of the associated parameters from all threeconvergent magnifier lenses 56.1′, L₁; 56.2′, L₂; third 56.3′, L₃, inview of the associated modulation surface 92, 92′ being located withinthe associated first-aspect optical subsystem 14, 14.1 at an associatedaperture stop 28.

Accordingly, the magnifier-lens prescription design process 4900provides for using common optical design approaches to design/prescribean optimized Fresnel magnifier lens 56.2, L₂, 130, 130′ that willprovide for forming a virtual image 16′″—having a relatively large fieldof view—of a relatively small flat-panel two-dimensional image-displaymodulation array 94 through a relatively-large exit pupil 18, subject tothe availability of sufficient light 16′ emanating from such flat-paneltwo-dimensional image-display modulation array 94 that is sufficient tofully illuminate the exit pupil 18.

Referring to FIGS. 47 and 50, the conditioner-lens prescription designprocess provides for determining the prescription of the Fresnelconditioner lens 56.1, L₁, 132 of the associated third-embodimentsecond-aspect optical subsystem 14, 14.2′″ incorporating the optimizedFresnel magnifier lens 56.2, L₂, 130, 130′ that resulted from themagnifier-lens prescription design process 4900. More particularly, instep (5002), and referring again to FIG. 47, the associatedthird-embodiment third-aspect near-eye display system 10, 10.3, 10.3′″is first configured in accordance with the parameters of thehypothetical-embodiment second-aspect near-eye display system 10.2,10.2′″ that were defined during, or determined by, the magnifier-lensprescription design process 4900, supra. Furthermore, in step (5004),additional parameters peculiar to the third-embodiment second-aspectoptical subsystem 14, 14.2′″, including 1) the curvature and extent ofthe surface 18″ of the exit pupil 18 and the associated concave-curvedsubpupil surface 84, 84″ thereat; 2) the distance Dc (illustrated inFIG. 19) between the flat-panel two-dimensional image-display modulationarray 94 and the Fresnel conditioner lens 56.1, L₁, 132; 3) and thedistance Ds (illustrated in FIG. 19) between the Fresnel conditionerlens 56.1, L₁, 132 and the curved modulation surface 92, 92″ of thecurved two-dimensional light-source array 106 of the associated subpupilmodulator 30, 30.3; and 4) the thickness t of the Fresnel conditionerlens 56.1, L₁, 132. For example, further to the embodiment used toillustrate the magnifier-lens prescription design process 4900, supra,the 20 millimeter diameter of the perimeter of exit pupil 18 defined instep (4902) forms the perimeter of a concave geometric surface construct82, 82′ that bounds a concave-curved subpupil surface 84, 84″ of 12.5millimeter radius representing a generalized radius of the eyeball ofthe human eye 20. Furthermore, a 1.5 millimeter thick Fresnelconditioner lens 132 is positioned 8 millimeters (Dc) beyond theflat-panel two-dimensional image-display modulation array 94, i.e. by adistance that is sufficient to preclude visibility of the associatedFresnel structure or structures 134′ of the Fresnel conditioner lens56.1, L₁, 132 as viewed through the optimized Fresnel magnifier lens56.2, L₂, 130, 130′, and sufficient to preclude possible moiré effectsbetween the Fresnel structure or structures 134′ of the Fresnelconditioner lens 56.1, L₁, 132 and the flat-panel two-dimensionalimage-display modulation array 94. Yet further, the curved modulationsurface 92, 92″ of a curved two-dimensional light-source array 106 islocated 42 millimeters (Ds) beyond the Fresnel conditioner lens 56.1,L₁, 132.

Notwithstanding that in actuality light 16′ associated with theexit-pupil image 18′ propagates from the curved two-dimensionallight-source array 106 to the exit pupil 18, the conditioner-lensprescription design process 5000 instead follows the light 16′ inreverse from the surface 18″ of the exit pupil 18, then through theoptimized Fresnel magnifier lens 56.2, L₂, 130, 130′, then through theflat-panel two-dimensional image-display modulation array 94 acting as adesign aperture stop 142, then through the Fresnel conditioner lens56.1, L₁, 132, and finally imaged thereby onto the curved modulationsurface 92, 92″ of the curved two-dimensional light-source array 106 ofthe associated subpupil modulator 30, 30.3, thereby effectively treatingthe concave-curved subpupil surface 84, 84″ as a design object surface144 being imaged by the third-embodiment third-aspect near-eye displaysystem 10, 10.3, 10.3′″, with the associated resulting lightdistribution being imaged at the curved modulation surface 92, 92″ thatis effectively treated as the associated design image surface 146 ofthat design object surface 144, wherein the flat-panel two-dimensionalimage-display modulation array 94 also functions as an associatedaperture stop 28 of the associated third-embodiment second-aspectoptical subsystem 14, 14.2′″ because any subpupil location will passlight 16′ from all locations on the flat-panel two-dimensionalimage-display modulation array 94. Accordingly, based upon the resultsof the magnifier-lens prescription design process 4900, for thisexample, the diameter of the aperture stop 28 is approximately 39millimeters, which corresponds to the diagonal measurement, supra, ofthe flat-panel two-dimensional image-display modulation array 94.

For example, FIG. 47 illustrates ray tracings of three sets of lightrays emanating from three different locations along the design objectsurface 144 (i.e. the concave-curved subpupil surface 84, 84″)—rangingfrom 0 to 10 millimeters in the vertical direction—through thethird-embodiment second-aspect optical subsystem 14, 14.2′″. Althoughthe full 10 millimeter range of the vertical subpupil surface is likelyunnecessary to view the entire image because—per the design parametersestablished in step (4902)—the vertical field of view is smaller thanthe horizontal field of view, the full vertical extent has beenillustrated in order to illustrate the prospective propagation ofperipheral light rays through the third-embodiment second-aspect opticalsubsystem 14, 14.2′″.

The third-embodiment third-aspect near-eye display system 10, 10.3,10.3′″ incorporating the optimized Fresnel magnifier lens 56.2, L₂, 130,130′ generates a virtual image 16′″ of the flat-panel two-dimensionalimage-display modulation array 94 through the exit pupil 18 of theassociated third-embodiment second-aspect optical subsystem 14, 14.2′″of the same image quality as achieved by the magnifier-lens prescriptiondesign process 4900.

The conditioner-lens prescription design process 5000 provides fordetermining both the prescription of an optimized Fresnel conditionerlens 56.1, L₁, 132′ and the shape of the associated design image surface146 (the curved modulation surface 92, 92″) that, in cooperation withthe optimized Fresnel magnifier lens 56.2, L₂, 130, 130′, will providefor forming an optimal real design image 146′ of the design objectsurface 144 (the concave-curved subpupil surface 84, 84″) at the designimage surface 146 (the curved modulation surface 92, 92″), based uponthe assumption that the exit-pupil image 18′—at the design objectsurface 144 (the concave-curved subpupil surface 84, 84″)—of the designimage surface 146 (the curved modulation surface 92, 92″) by theoptimized Fresnel conditioner lens 56.1, L₁, 132′, in cooperation withthe optimized Fresnel magnifier lens 56.2, L₂, 130, 130′, will besimilarly optimized, wherein as used herein, the term optimized isassociated with a configuration associated with an extremum (e.g.minimum) of an associated merit, or objective, function, e.g.peak-to-valley spot size. Accordingly, following the definition in steps(5002) and (5004) of the parameters of the third-embodimentsecond-aspect optical subsystem 14, 14.2′″, in step (5006), theoperation of the third-embodiment second-aspect optical subsystem 14,14.2′″ is simulated using optical design software, for example, Zemaxoptical design software, so as to provide for optimizing—in step (5008)—higher order Fresnel prescriptions of both sides of the Fresnelconditioner lens 132, for example, under the constraint of limiting theone or both surfaces to vary only in second and higher order asphericparameters (with the general radius and conic parameters being of minorconcern), and to provide for optimizing—also in step (5008)—the radiusand conic constant of the curved modulation surface 92, 92″, using anoptimization merit function designed to minimize the spot size of theimages formed on the curved modulation surface 92, 92″ from a variety oflocations on the design object surface 144 (the concave-curved subpupilsurface 84, 84″), for example, with the optimization providing forminimizing an optical design merit function given by the two-dimensionalpeak-to-valley spot size of the design image 146′ formed at multiplelocations at the curved modulation surface 92, 92″ of the curvedtwo-dimensional light-source array 106, generally as the weighted sum ofthe two-dimensional peak-to-valley spot sizes from the differentlocations. In accordance with one set of embodiments, each of thedifferent locations is weighted equally.

For example, during the optical design simulation, a light distributionat the concave-curved subpupil surface 84, 84″ of the exit pupil 18acting as the design object surface 144 is back-propagated through theoptimized Fresnel magnifier lens 56.2, L₂, 130, 130′, then through theflat-panel two-dimensional image-display modulation array 94 acting asthe design aperture stop 142, then through the Fresnel conditioner lens56.1, L₁, 132 being optimized, and then onto the curved modulationsurface 92, 92″ of the curved two-dimensional light-source array 106acting as the design image surface 146, so as to form a correspondingdesign image 146′, from which the associated optical design meritfunction is evaluated. Although functioning like a collimator orcondenser lens, the optimized Fresnel conditioner lens 56.1, L₁, 132′will not necessarily strictly conform to such classical configuration,but instead is configured to best support an imaging relationshipbetween the curved modulation surface 92, 92″ and the concave-curvedsubpupil surface 84, 84″ of the third-embodiment second-aspect opticalsubsystem 14, 14.2′″, while providing for fully illuminating theassociated flat-panel two-dimensional image-display modulation array 94.

The results of the optical design simulation of the conditioner-lensprescription design process 5000 indicate that the central imagelocation provided for a relatively better imaging relationship betweenthe curved modulation surface 92, 92″ and the concave-curved subpupilsurface 84, 84″ than did locations that were relatively peripheralthereto. In the context of the third-embodiment third-aspect near-eyedisplay system 10, 10.3, 10.3′″, this relatively-higher image quality atthe relatively-central locations may result in a sufficiently-highdepth-of-field and image clarity so that the associated Fresnelstructure or structures 134′ becomes visible to the user 22. If so, thiscan be mitigated by providing for a relatively-lower image quality atrelatively-central locations while relatively-more-highly weightingrelatively-peripheral locations that are inherently more blurry,relative to the weighting of relatively-central locations. Moregenerally, relatively weighting of various locations is based upon theparticular intended imaging performance of the associated near-eyedisplay system 10, 10.2, 10.2′, 10.2″, 10.3, 10.3′, 10.3″, 10.3′″, 10.4,10.4′, 10.4″ being optimized.

When optimizing any optical system one can allow any parameter of thatsystem to vary as a parameter to be optimized. For example, for opticalelements for which thickness is not constrained to a fixed value (e.g.other than Fresnel lenses having predetermined thicknesses) a thicknessof an optical element at any point on the element can be constrained soas to either, or both, not exceed a maximum value nor be less than aminimum value, while providing the associated optimization process withthe flexibility to vary the element thickness within that range. Theprescription of a conventional (i.e. non-Fresnel) optical element isactually a variation in thickness as a function of distance from anoptical axis. Accordingly, it is common practice to provide thatflexibility to the optimization process while constraining the thicknessto be within reasonable limits, for example, greater than apredetermined minimum positive thickness, and less than a maximumthickness associated with a lens that would otherwise either benon-manufacturable or excessively heavy or bulky. These parameters withassociated limitations are included in the optimization process andassociated constraints, along with the general image qualityfunctionality, for example, the spot size calculations that are includedin the associated merit function. In practice, a “centroid” image ray iscomputed for each field (object) location and then the merit function isevaluated for a series of test field locations in proximity to thatcentroid, wherein how many and how distributed are accordance with oneor more parameters of the optical design software. The optical designsoftware then calculates the distance between each test ray arrivallocation at the image surface and the centroid location to build up amyriad of samples, for example, with ultimately thousands of rays beingtraced from the various locations.

Referring again to FIG. 47, the shape of the optimized curved modulationsurface 92, 92′″ resulting from the conditioner-lens prescription designprocess 5000 is generally a paraboloid. Despite optimization, opticalrays from subpupil point locations on the concave-curved subpupilsurface 84, 84″ do not fully converge at corresponding point locationson the corresponding associated optimized curved modulation surface 92,92″, with decreasing quality toward the periphery thereof. As aconsequence, any controllable light source 97 placed relatively moreperipherally from the optical axis 36 on the curved modulation surface92, 92″ will not form an ideal corresponding image as an exit subpupil32 on the concave-curved subpupil surface 84, 84″. These imperfectlyformed exit subpupils 32 would be accounted for in the design of theassociated Active Subpupil Region (ASR) 72 of the resulting near-eyedisplay system 10, 10.2, 10.2′, 10.2″, 10.3, 10.3′, 10.3″, 10.3′″, 10.4,10.4′, 10.4″ because in some cases they might be larger than the eyepupil 38, or they might overlap other exit subpupils 32. However, as istypical with on-axis optical systems generally, the relatively centralregion of the third-embodiment second-aspect optical subsystem 14,14.2′″ provides better imaging forming properties than relativelyperipheral regions. Accordingly, the Active Subpupil Region (ASR) 72 canbe designed to be relatively small in the central region re of theconcave-curved subpupil surface 84, 84″ proximate to the optical axis36, and because this is the region that is primarily occupied by the eyepupil 38 of the user 22 when viewing the virtual image 16′″, the abilityto improve spatial clarity by providing an Active Subpupil Region (ASR)72 smaller than the eye pupil 38 of the user 22 even in this relativelysmaller region can be beneficial.

Although generally a Fresnel surface 134 may be applied to one or bothof the opposing surfaces of the 1.5 millimeter thick Fresnel magnifierlens 130, the results of the associated optimization processes—i.e. thevalue(s) of the associated merit function(s)—have been found tosubstantially better if a high order aspheric Fresnel surface 134 can beapplied to both surfaces, rather than just to one, particularly if arelatively high magnification is desired, notwithstanding that twoopposing Fresnel surfaces 134—each with a corresponding Fresnelstructure 134′, —will produce more scattered extraneous light 16 ^(iv)than a would a single Fresnel surface 134, because the use of modulatedsubpupils 32′ provides for reducing or minimizing scattered extraneouslight 16 ^(iv) that would otherwise be visible through the eye pupil 38.

Alternatively, referring to FIG. 51, in accordance with one set ofembodiments, the Fresnel magnifier lens 56.2, L₂, 130, 148 may comprisea hybrid lens 148 comprising a conventional convex refractive surface150 on a front side 148.1 thereof, and a Fresnel surface 134 on the rearside 148.2 thereof, wherein when incorporated in the third-embodimentthird-aspect near-eye display system 10, 10.3, 10.3′″, the Fresnelmagnifier lens 56.2, L₂, 130, 148 is oriented with the front side 148.1facing the exit pupil 18 so as to mitigate against scattering ofextraneous light 16 ^(iv) that would otherwise occur with a front-facingFresnel surface 134 instead of the front-facing conventional convexrefractive surface.

In practice, the ideal profile of a Fresnel surface 134 of a Fresnellens 130, 132 is determined through optical design as a continuousfunction based upon the propagation of rays that extend to theunderlying planar surface of the associated Fresnel surface 134, afterwhich the manufacturer of the Fresnel lens 130, 132 would import thatinformation, along with other parameters, into associated CNC diamondturning software to determine the corresponding associated actual groovestructure profile of the Fresnel structure 134′.

The use of Fresnel lenses 130, 132 in the third-embodiment second-aspectoptical subsystem 14, 14.2′″ provides for a relatively compact,light-weight, wide field-of-view third-embodiment third-aspect near-eyedisplay system 10, 10.3, 10.3′″ with a relatively-large exit pupil 18,which together with the eye-tracking subsystem 42, the subpupilmodulation controller 50, and the curved two-dimensional light-sourcearray 106 arranged to conform to the optimized curved modulation surface92, 92′″, and the associated control thereof in accordance with anassociated subpupil modulation scheme 70, 70.1, 70.2, 70.3, supra,provides for a third-embodiment third-aspect near-eye display system 10,10.3, 10.3′″ with relatively higher contrast and relatively-higherclarity of the relatively-central region of the image 16, usingsubstantially less illumination power than would a near-eye displaysystem that did not otherwise use a controllable light source 97.

The actual size of the exit subpupils 32 in a near-eye display system10, 10.1, 10.2, 10.2′, 10.2″, 10.3, 10.3′, 10.3″, 10.3′″, 10.4, 10.4′,10.4″ will depend upon a plurality of associated design factors andconsiderations. For example, an exit subpupil 32 made so small as tosignificantly increase the depth of field of the image through that exitsubpupil 32 may reveal structures located relatively distally along theoptical axis 36 from the flat-panel two-dimensional image-displaymodulation array 94—such as the structures of the Fresnel magnifier lens56.2, L₂, 130 or the Fresnel conditioner lens 56.1, L₁, 132, —overlayedwith the image 16. To the other extreme, an exit subpupil 32 larger thanthe eye pupil 38 will not provide for the improvement in clarity of theimage 16 through that exit subpupil 32 that would otherwise be possible.The actual size of an exit subpupil 32 may be further dependent on theimaging capabilities of the optical subsystem 14, 14.1, 14.2, 14.2′,14.2″, 14.2′″ to form a proper image of the associated subpupilmodulator 30, i.e. either the flat-panel two-dimensional modulationarray 58 or the associated controllable light source 97. Indeed theassociated light-modulating pixels 60/light source elements 100 of thesubpupil modulator 30 themselves will in practice each span a finitesize, rather than being point pixel or source elements. Accordingly,while any reduction of light 16′ through the exit pupil 18 of theoptical subsystem 14, 14.1, 14.2, 14.2′, 14.2″, 14.2′″ by deactivatingat least some of an array of relatively smaller exit subpupils 32 willprovide improvements in contrast and power usage, and the degree of suchbenefits, and the possibility of improved clarity, will be dependent onthe actual implementation of the subpupil modulator 30, 30.1, 30.2,20.3, 30.4.

Each of the second-, third—and fourth-aspect near-eye display systems10, 10.2, 10.3, 10.4 provide for using a subpupil modulator 30, 30.2,30.3, 30.4 incorporating a controllable light source 97 that cooperateswith an associated modulation surface 92 to provide for generating aplurality of exit subpupils 32 and an associated subpupil surface 84,wherein the modulation 92 and subpupil 84 surfaces are images of eachother as provided for by the associated optical subsystem 14, 14.2,14.2′, 14.2″, 14.2′″, which also provides for the controllable lightsource 97 to illuminate the entirety of an associated flat-paneltwo-dimensional image-display modulation array 94 for each of the exitsubpupils 32. The associated conditioner lens 102, 102′, L₁ provides forgathering light 16′ from the relatively-distant (both with respect toalong the optical axis 36 and transverse thereto) controllable lightsource 97 in order to provide illuminating the entirety of theassociated flat-panel two-dimensional image-display modulation array 94for each of the exit subpupils 32. Accordingly, the associated volume ofspace between the controllable light source 97 and the flat-paneltwo-dimensional image-display modulation array 94 that provides for thisfunctionality can be considerable, and potentially limiting to theprospective compactness of the associated second-, third—orfourth-aspect near-eye display system 10, 10.2, 10.2′, 10.2″, 10.3,10.3′, 10.3″, 10.4, 10.4′, 10.4″.

Referring to FIGS. 52-53, a waveguide projector 152—modeled as aflat-panel two-dimensional image-display array 52 in cooperation with anideal paraxial lens 154 located one focal-length F therefrom—providesfor generating, per the model illustrated in FIG. 53, what would be afar-field light distribution 156 of light 16′ emanating from aflat-panel two-dimensional image-display array 52, i.e. a plurality ofsets of collimated rays, each ray of each set emanating from acorresponding light-emitting image-display pixel 54 effective pointsource of the flat-panel two-dimensional image-display array 52, andpropagating at an angle from the optical axis 36 that is responsive tothe lateral offset of the corresponding associated light-emittingimage-display pixel 54 point source. Accordingly, the far-field lightdistribution 156 provides a virtual image of the flat-paneltwo-dimensional image-display array 52 through the exit pupil 158 of thewaveguide projector 152. In one set of embodiments, the waveguideprojector 152 comprises a conventional optical system placed in front ofa flat panel of image-display pixels to project collimated light fromthose pixels as a virtual image through the exit pupil of that opticalsystem, which light is thereafter directed or “coupled” into an opticalwaveguide where the light travels through multiple internal reflectionsuntil interacting with features within the waveguide which redirect or“decouple” the collimated light out of the waveguide into an expandedexit pupil 158. If the associated exit pupil 158 can be madesufficiently large to fill a flat-panel two-dimensional image-displaymodulation array 94 of the second—or third-aspect near-eye displaysystem 10, 10.2, 10.2′, 10.2″, 10.3, 10.3′, 10.3″, 10.3′″, then thelight-emitting image-display pixels 54 of the waveguide projector 152can act as a flat-panel two-dimensional light-source array 98 of acontrollable light source 97 of an associated subpupil modulator 30,30.2 of the second—aspect near-eye display system 10, 10.2, 10.2′,10.2″, with the light from each controllable light source 97 emergingsubstantially collimated as is typical of waveguide projectors 152. Forexample, U.S. Pat. Nos. 10,732,415 and 10,627,565—each incorporated byreference in its entirety—disclose a substrate-guide optical device, anda waveguide display assembly, respectively, either of which could beused as a waveguide projector 152 in cooperation with a second-aspectoptical subsystem 14, 14.2, 14.2′, 14.2″, 14.2′″ of a second—orthird-aspect near-eye display system 10, 10.2, 10.2′, 10.2″, 10.3,10.3′, 10.3″, 10.3′″ so as to provide for improving the compactnessthereof, wherein, for application to a second-aspect near-eye displaysystem 10, 10.2, 10.2′, 10.2″, the waveguide projector 152 would alsosupplant the conditioner lens 102, 102′, L₁, and for application to athird-aspect near-eye display system 10, 10.3, 10.3′, 10.3″, thewaveguide projector 152 would be used in cooperation with the associatedconditioner lens 102, 102′, L₁, the latter of which would provide forconditioning the collimated light from the waveguide projector 152 so asto provide for generating—in cooperation with the associated convergentmagnifier lens 56.2′, 130, 130′, L₂—a concave-curved subpupil surface84, 84″ at the exit pupil 18, or an approximation thereto.

Referring to FIGS. 54 and 55, a first embodiment 10.5′ of a fifth-aspectnear-eye display system 10, 10.5, 10.5′ is similar to thethird-embodiment third-aspect near-eye display system 10, 10.3, 10.3′″,supra, except that the curved two-dimensional light-source array 106 andthe upper fold mirror 136.1 are replaced with a waveguide projector 152constituting an associated fifth aspect of a subpupil modulator 30,30.5. The waveguide projector 152 incorporates a controllable lightsource 97 that defines an array of modulated subpupils 32′, and incooperation with an alternative Fresnel conditioner lens 56.1, L₁, 132″and the associated Fresnel magnifier lens 56.2, L₂, 130, 148,collectively constitute an associated third-aspect optical subsystem 14,14.3, wherein the combination of the waveguide projector 152, Fresnelconditioner lens 56.1, L₁, 132, and flat-panel two-dimensionalimage-display modulation array 94 constitute a fifth-aspect imagegenerator 12, 12.5. The waveguide projector 152 is under control of thesubpupil modulation controller 50, responsive to the eye-trackingsubsystem 42. The first-embodiment fifth-aspect near-eye display system10, 10.5, 10.5′ further illustrates incorporation of a hybrid Fresnelmagnifier lens 56.2, L₂, 130, 148 that is illustrated individually inFIG. 51, supra, which provides for reducing possible scattering from theassociated Fresnel structure 134′ to occurrence from only the rear side148.2—facing away from the user 22—of the hybrid lens 148 relative to aFresnel magnifier lens 56.2, L₂, 130 incorporating Fresnel surfaces 134on both sides thereof.

When applying the conditioner-lens prescription design process 5000,supra, to the Fresnel conditioner lens 56.1, L₁, 132, the resultingoptimized alternative Fresnel conditioner lens 56.1, L₁, 132′″ resultedin a subpupil surface 84, 84′ that was mildly convex—i.e. a convexsubpupil surface 84, 84′″—relative to the eye 20 of the user 22, ratherthan an ocularly-conforming concave-curved subpupil surface 84, 84″.

Notwithstanding that the waveguide projector 152 can producewell-focused exit subpupils 32 on the resulting convex subpupil surface84, 84′, those exit subpupils 32 form on the convex subpupil surface 84,84′ from which the associated concentrated light 16′ of the image 16 ispoorly accessible to the eye pupil 38 over the entire range of normalrotation of the eye 20, so that the associated first-embodimentfifth-aspect near-eye display system 10, 10.5, 10.5′ will effectivelypresent relatively-larger exit subpupils 32 to the eye 20 at manyassociated rotational angles thereof. Accordingly, notwithstanding thatthe first-embodiment fifth-aspect near-eye display system 10, 10.5,10.5′ can provide for reduced power usage by deactivating—at any giventime—exit subpupils 32 that are not visible thereto, and can provide anexceptional imaging relationship between the flat-panel two-dimensionalimage-display modulation array 94 and the convex subpupil surface 84,84′, the resulting imaging performance for the user 22 is relativelyinferior to what would otherwise result with relatively smaller exitsubpupils 32.

Referring to FIG. 56, a second embodiment 10.5″ of a fifth-aspectnear-eye display system 10, 10.5, 10.5″ is the same as to thefirst-embodiment fifth-aspect near-eye display system 10, 10.5, 10.5′,supra, except for further incorporating in an associated fourth-aspectoptical subsystem 14, 14.4, a varifocal lens 160 between the waveguideprojector 152 and the Fresnel conditioner lens 56.1, L₁, 132″, whereinthe combination of the waveguide projector 152, varifocal lens 160,Fresnel conditioner lens 56.1, L₁, 132, and flat-panel two-dimensionalimage-display modulation array 94 constitute a sixth-aspect imagegenerator 12, 12.6. For example, U.S. Pat. No. 10,627,565, which isincorporated herein by reference in its entirety, discloses anelectronic varifocal lens at the exit of the waveguide of a waveguidedisplay so as to provide for changing the apparent distance of thevirtual image exiting the waveguide in order to accommodate, inter alia,user preferences. The varifocal lens 160—under control of the subpupilmodulation controller 50 responsive to the eye-tracking subsystem42—provides for changing the distance between the subpupil surface 84,84′ and the optimized Fresnel magnifier lens 56.2, L₂, 130, 130′. Undertypical use of the second-embodiment fifth-aspect near-eye displaysystem 10, 10.5, 10.5″, the distance between the eye 20 of the user 22and the associated fourth-aspect optical subsystem 14, 14.4 isrelatively fixed. Accordingly, the varifocal lens 160 can be used toposition a single exit subpupil 32 or small cluster of exit subpupils32—for example, of the Active Subpupil Region (ASR) 72, —at acontrollable distance from the eye 20 of the user 22, for example, so asto continuously position the Active Subpupil Region (ASR) 72 at thelocation of the eye pupil 38 of the user 22 responsive to theeye-tracking subsystem 42, thereby effectively creating a dynamicallychanging subpupil surface 84 that effectively conforms to the eye pupil38 regardless of the orientation thereof. If the second-embodimentfifth-aspect near-eye display system 10, 10.5, 10.5″ were to furtherprovide for detecting the distance between the eye pupil 38 of the user22 to the flat-panel two-dimensional image-display modulation array 94,then the entire volumetric visual environment (VVE) 80 of thefourth-aspect optical subsystem 14, 14.4 can be accessed with adynamically positioned exit subpupil 32 wherever the eye pupil 38 of theuser 22 is positioned, so as to provide for a compact, lightweight andflexible near-eye display system that can provide for a relatively largefield of view and a relatively high image quality, while usingsubstantially less power than would otherwise be required to illuminatethe entire exit pupil 18 of the associated optical subsystem.

Referring to FIG. 57, a third embodiment 10.5′″ of a fifth-aspectnear-eye display system 10, 10.5, 10.5′″ is the same as the secondaspect near-eye display system 10, 10.2, supra, illustrated in FIG. 16,except that both the controllable light source 97 provided for by theflat-panel two-dimensional light-source array 98 of associatedlight-source elements 100, and the associated conditioner lens 102,102′, L₁, are replaced with a waveguide projector 152 that ideallyfunctions in accordance with the model illustrated in FIG. 53, supra,and which therefor provides for substantially the same functionality asthe controllable light source 97 in cooperation with the conditionerlens 102, 102′, L₁ of the second aspect near-eye display system 10,10.2. Accordingly, each point source of light 16′ by an associatedillumination pixel within the waveguide projector 152 provides forgenerating a corresponding beam 64 of light 16′ that propagates at anangle relative to the optical axis 36 that is responsive to the lateraloffset relative to the optical axis 36 of the associated point source oflight within the waveguide projector 152, and which illuminates theentirety of the associated flat-panel two-dimensional image-displaymodulation array 94—in accordance with an associated fifth-aspect imagegenerator 12, 12.5—which, in cooperation with an associated seconddioptric-power optical element 56, 56.2, L₂ acting as an associatedmagnifier lens 56, 56.2, L₂ of an associated fifth-aspect opticalsubsystem 14, 14.5 provides for generating an associated virtual image16′″ of the flat-panel two-dimensional image-display modulation array 94for each exit subpupil 32 that is projected onto the associated planarsubpupil surface 84, 84′ at the exit pupil 18, as described herein abovein respect of the second aspect near-eye display system 10, 10.2.

The third-embodiment fifth-aspect near-eye display system 10, 10.5,10.5′″ may optionally further include—in an associated sixth-aspectoptical subsystem 14, 14.6—a varifocal lens 160 located between thewaveguide projector 152 and the flat-panel two-dimensional image-displaymodulation array 94—of an associated sixth-aspect image generator 12,12.6—and under control of the associated eye-tracking subsystem 42, soas to provide for controlling the axial location of the planar subpupilsurface 84, 84′ to be substantially aligned with that of the eye pupil38 of the user 22 for the exit subpupils 32 of the associated ActiveSubpupil Region (ASR) 72 being displayed.

Referring to FIG. 58, a fourth embodiment 10.5″″ of a fifth-aspectnear-eye display system 10, 10.5, 10.5″″ is the same as thethird-embodiment fifth-aspect near-eye display system 10, 10.5, 10.5′″,supra, illustrated in FIG. 57, except for optionally furtherincorporating—in an associated seventh-aspect optical subsystem 14,14.7—a conditioner lens 102, 102′, L₁ located between the waveguideprojector 152 and the flat-panel two-dimensional image-displaymodulation array 94, so as to provide for compensating for non-ideal,i.e. realistic, optical elements within the associated seventh-aspectoptical subsystem 14, 14.7, the latter of which incorporates at leastthe magnifier lens 56, 56.2, L₂, the flat-panel two-dimensionalimage-display modulation array 94, and the waveguide projector 152, andwhich may optionally include one or both of the conditioner lens 102,102′, L₁ and a varifocal lens 160. The conditioner lens 102, 102′, L₁can further provide for forming a non-planar subpupil surface 84 at theexit pupil 18, wherein the particular configuration of the associatedcomponents thereof is not limiting. For example, a real,practically-produced magnifier lens 56, 56.2, L₂, may includeaberrations that might otherwise preclude an ideal formation ofassociated images of the controllable light sources 97 of the associatedexit subpupils 32. Accordingly, even with an ideal light distributionilluminating the flat-panel two-dimensional image-display modulationarray 94, the conditioner lens 102, 102′, L₁ works in cooperation withthe magnifier lens 56, 56.2, L₂ to provide for compensating foraberrations in the magnifier lens 56, 56.2, L₂ that might otherwiseadversely affect either the associated subpupil surface 84, or the imageof the associated exit subpupils 32 therein.

A real magnifier lens 56, 56.2, L₂—which may be imperfect—may notnecessarily generate a sharply focused image of an exit subpupil 32 onthe subpupil surface 84 from a corresponding associated beam ofcollimated light that is incident upon the flat-panel two-dimensionalimage-display modulation array 94, and that was generated by acorresponding associated controllable light source 97. Generally, arelatively-smaller size of the associated exit subpupils 32 isbeneficial to providing for a relatively greater control of light 16′through the eye pupil 38, provided that the exit subpupils 32 areco-located with the eye pupil 38. Although a planar subpupil surface 84,84′ can provide for relatively smaller exit subpupils 32 than aconcave-curved subpupil surface 84, 84″, the difference is generally notsufficient to overcome the adverse effects of axial misalignment whenthe eye pupil 38 rotates away from the planar subpupil surface 84, 84′.However, the varifocal lens 160 can provide for dynamically creating aneffective concave-curved subpupil surface 84, 84″—notwithstanding therebeing a planar subpupil surface 84, 84′—by axially positioning theplanar subpupil surface 84, 84′ so that the associated exit subpupils 32thereon of the associated Active Subpupil Region (ASR) 72 are maintainedin axial alignment with the eye pupil 38. As a result of theconditioner-lens prescription design process 5000, it has beendiscovered that under at least some circumstances, that a convexsubpupil surface 84, 84′″ provides for the relatively-smallest andmost-highly-focused exit subpupils 32, which can be accommodated byusing the varifocal lens 160 to provide for maintaining an axialalignment of the exit subpupils 32 of the associated Active SubpupilRegion (ASR) 72 on the convex subpupil surface 84, 84′ in axialalignment with the eye pupil 38.

It should be understood that the magnifier-lens 4900 andconditioner-lens 5000 prescription design processes can be generallyapplied to any of the above-described near-eye display systems 10, 10.1,10.1, 10.2′, 10.2″, 10.2′, 10.3, 10.3′, 10.3″, 10.3′″, 10.4, 10.4′,10.4″, 10.5, 10.5′, 10.5″, 10.5′″, 10.5″″, notwithstanding detailedillustration thereof in the context of the third-embodimentsecond-aspect optical subsystem 14, 14.2′″.

In accordance with one set of embodiments, a near-eye display system(10, 10.1, 10.2, 10.3, 10.4) for displaying an image (16) to an eye (20)of a user (22) of the near-eye display system (10, 10.1, 10.2, 10.3,10.4), incorporates: a) an image generator (12, 12.1, 12.2, 12.3, 12.4),wherein the image generator (12, 12.1, 12.2, 12.3, 12.4) provides forgenerating light (16′) of the image (16) responsive to an electronicimage signal (74), and the light (16′) of the image (16) is projectableonto a retina (24) of the eye (20) of the user (22) when the near-eyedisplay system (10, 10.1, 10.2, 10.3, 10.4) is used by the user (22); b)an optical subsystem (14, 14.1, 14.2, 14.2′, 14.2″, 14.2′″), wherein theoptical subsystem (14, 14.1, 14.2, 14.2′, 14.2″, 14.2′″) operates incooperation with the image generator (12, 12.1, 12.2, 12.3, 12.4) toprovide for projecting the image (16) onto the retina (24) of the eye(20) of the user (22) when the near-eye display system (10, 10.1, 10.2,10.3, 10.4) is used by the user (22); and a subpupil modulator (30,30.1, 30.2, 30.3, 30.4), wherein at least a portion of the opticalsubsystem (14, 14.1, 14.2, 14.2′, 14.2″, 14.2′″) forms an exit-pupilimage (18′) of the subpupil modulator (30, 30.1, 30.2, 30.3, 30.4) in anexit pupil (18) of the near-eye display system (10, 10.1, 10.2, 10.3,10.4), the exit pupil (18) is located proximate to an eye pupil (38) ofthe eye (20) of the user (22) when the near-eye display system (10,10.1, 10.2, 10.3, 10.4) is used by the user (22), the subpupil modulator(30, 30.1, 30.2, 30.3, 30.4) provides for controllably forming at leastone subpupil (32) within the exit pupil (18), an area of at least onesubpupil (32) is less than an area of the exit pupil (18); and whenactivated, each at least one subpupil (32) incorporates the light (16′)from an entirety of the image (16). The near-eye display system (10,10.1, 10.2, 10.3, 10.4) may further incorporate an eye-trackingsubsystem (42), wherein the eye-tracking subsystem (42) incorporates: a)an infrared illuminator (44) positioned and configured so as to providefor illuminating at least the eye pupil (38) of the eye (20) for a rangeof gaze directions (34) of the eye (20); b) an infrared-responsivecamera (46) positioned and configured so as to provide for acquiring animage of at least the eye pupil (38) of the eye (20) for the range ofgaze directions (34) of the eye (20); and c) an eye-tracking processor(48), wherein the eye-tracking processor (48) provides for generating atleast a measure of a location of the eye pupil (38) of the eye (20), andthe eye-tracking processor (48) provides for communicating the at leastthe measure of the location of the eye pupil (38) of the eye (20), to asubpupil modulation controller (50), wherein the subpupil modulationcontroller (50) may provide for identifying an Active Subpupil Region(72) within the subpupil modulator (30, 20.1, 30.2, 30.3, 30.4)responsive to at least the measure of the location of the eye pupil (38)of the eye (20) from the eye-tracking subsystem (42), the subpupilmodulation controller (50) may provide for activating at least onemodulated subpupil (32′) within the Active Subpupil Region (72) so as tocause a corresponding at least one subpupil (32) within the exit pupil(18) to become activated, and the subpupil modulation controller (50)may provide for deactivating each remaining modulated subpupil (32′)that is not within the Active Subpupil Region (72) so as to cause eachremaining at least one subpupil (32) within the exit pupil (18) tobecome deactivated, wherein the Active Subpupil Region (72) may surrounda location corresponding to the location of the eye pupil (38) of theeye (20); a size of the Active Subpupil Region (72) may be independentof the location of the eye pupil (38) of the eye (20); the ActiveSubpupil Region (72) may be circularly shaped; the eye-trackingsubsystem (42) may further provide for determining and communicating tothe subpupil modulation controller (50) at least one measure selectedfrom the group consisting of a measure of a shape of the eye pupil (38)of the eye (20), and a measure of a size of the eye pupil (38) of theeye (20), and the Active Subpupil Region (72) is shaped similarly to theshape of the eye pupil (38) of the eye (20); and the Active SubpupilRegion (72) may be located entirely within the eye pupil (38) of the eye(20).

In accordance with one set of embodiments of first 10.1 and second 10.2aspects of the near-eye display system (10, 10.1, 10.2), the subpupilmodulator (30, 30.1, 30.2) incorporates at least one modulation element(90) located on or in cooperation with an associated modulation surface(92, 92′), the associated modulation surface (92, 92′) is substantiallyplanar, and the exit-pupil image (18′) of the associated modulationsurface (92, 92′) is located on a corresponding substantially planarsubpupil surface (84, 84′).

In accordance with one set of embodiments of the first aspect 10.1 ofthe near-eye display system (10, 10.1): a) the image generator (12,12.1) comprises a flat-panel two-dimensional image-display array (26,52) of light-emitting image-display pixels (54), b) the opticalsubsystem (14, 14.1) comprises a first dioptric-power optical element(56, 56.1, 56.1′, L₁) located between the flat-panel two-dimensionalimage-display array (26, 52) of light-emitting image-display pixels (54)and a flat-panel two-dimensional modulation array (58) oflight-modulating pixels (60), the first dioptric-power optical element(56, 56.1, 56.1′, L₁) is located substantially one focal length fromeach of the flat-panel two-dimensional image-display array (26, 52) ofthe light-emitting image-display pixels (54) and a first side (58.1) ofthe flat-panel two-dimensional modulation array (58) of thelight-modulating pixels (60), c) the optical subsystem (14, 14.1)further comprises a second dioptric-power optical element (56, 56.2,56.2′, L₂) located between the flat-panel two-dimensional modulationarray (58) and the exit pupil (18), the second dioptric-power opticalelement (56, 56.2, 56.2′, L₂) is located substantially one focal lengthfrom a second side (58.2) of the flat-panel two-dimensional modulationarray (58), the first (58.1) and second (58.2) sides of the flat-paneltwo-dimensional modulation array (58) oppose one another, d) the opticalsubsystem (14, 14.1) further comprises a third dioptric-power opticalelement (56, 56.3, 56.3′, L₃) located between the second dioptric-poweroptical element (56, 56.2, 56.2′, L₂) and the exit pupil (18), thesecond dioptric-power optical element (56, 56.2, 56.2′, L₂) is locatedsubstantially one focal length from each of a remaining focal plane (62)of the second dioptric-power optical element (56, 56.2, 56.2′, L₂) andthe exit pupil (18), e) the subpupil modulator (30, 30.1) comprises theflat-panel two-dimensional modulation array (58) of the light-modulatingpixels (60), a transmissibility of the light (16′) through eachlight-modulating pixel (60) of the flat-panel two-dimensional modulationarray (58) of the light-modulating pixels (60) is individuallycontrollable responsive to a corresponding associated subpupilmodulation control signal (51) from a subpupil modulation controller(50), each the light-modulating pixel (60) of the flat-paneltwo-dimensional modulation array (58) of the light-modulating pixels(60) is associated with a corresponding at least one subpupil (32)within the exit pupil (18), and the exit pupil (18) is formed as theexit-pupil image (18′) responsive to a cooperation of the first (56,56.1, 56.1′, L₁), second (56, 56.2, 56.2′, L₂) and third (56, 56.3,56.3′, L₃) dioptric-power optical elements, and the exit pupil (18) issubstantially planar. The first dioptric-power optical element (56,56.1, 56.1′, L₁) may incorporate a first convergent magnifier lens(56.1′, L₁), the second dioptric-power optical element (56, 56.2, 56.2′,L₂) may incorporate a second convergent magnifier lens (56.1′, L₂), andthe third dioptric-power optical element (56, 56.3, 56.3′, L₃) mayincorporate a third convergent magnifier lens (56.1′, L₃), and eachlight-emitting image-display pixel (54) of the flat-paneltwo-dimensional image-display array (26, 52) of light-emittingimage-display pixels (54) may incorporate either a light-emitting diodeelement or a backlit liquid-crystal-display element.

In accordance with one set of embodiments of second 10.2, third 10.3,fourth 10.4 aspects of the near-eye display system (10, 10.2, 10.3,10.4): a) the image generator (12, 12.2, 12.3, 12.4) incorporates aflat-panel two-dimensional image-display modulation array (94) oflight-modulating image-display pixels (96, 96′) in cooperation with acontrollable light source (97) of the subpupil modulator (30, 30.2,30.3, 30.4), b) the optical subsystem (14, 14.2, 14.2′, 14.2″, 14.2′″)incorporates a first dioptric-power optical element (56, 56.1, 56.1′,L₁, 102, 102′) located between a first side (94.1) of the flat-paneltwo-dimensional image-display modulation array (94) of thelight-modulating image-display pixels (96, 96′) and the controllablelight source (97) of the subpupil modulator (30, 30.2, 30.3, 30.4),wherein the first dioptric-power optical element (56, 56.1, 56.1′, L₁,102, 102′) is located substantially one focal length from thecontrollable light source (97) of the subpupil modulator (30, 30.2,30.3, 30.4), and the first dioptric-power optical element (56, 56.1,56.1′, L₁, 102, 102′) is proximate to the first side of the flat-paneltwo-dimensional image-display modulation array (94) of thelight-modulating image-display pixels (96, 96′), c) the opticalsubsystem (14, 14.2, 14.2′, 14.2″, 14.2′″) further incorporates a seconddioptric-power optical element (56, 56.2, 56.2′, L₂) located between theflat-panel two-dimensional image-display modulation array (94) and theexit pupil (18), wherein the second dioptric-power optical element (56,56.2, 56.2′, L₂) is located substantially one focal length from each ofa second side (94.2) of the flat-panel two-dimensional image-displaymodulation array (94) and the exit pupil (18), and the first (94.1) andsecond (94.2) sides of the flat-panel two-dimensional image-displaymodulation array (94) oppose one another, and d) the controllable lightsource (97) of the subpupil modulator (30, 30.2, 30.3, 30.4) providesfor separately and controllably illuminating or not illuminating each atleast one subpupil (32) within the exit pupil (18) responsive to acorresponding associated subpupil modulation control signal (51) from asubpupil modulation controller (50). Each light-modulating image-displaypixel (96, 96′) of the flat-panel two-dimensional image-displaymodulation array (94) of the light-modulating image-display pixels (96,96′) may incorporate a liquid-crystal image-display pixel (96′). Thefirst dioptric-power optical element (56, 56.1, 56.1′, L₁, 102, 102′)may incorporate a plano-convex conditioner lens (102′, L₁), and a planarsurface (102.1′) of the plano-convex conditioner lens (102′, L₁) isproximate to the first side (94.1) of the flat-panel two-dimensionalimage-display modulation array (94). The second dioptric-power opticalelement (56, 56.2, 56.2′, L₂) may incorporate a second convergentmagnifier lens (56.2′, L₂). The second dioptric-power optical element(56, 56.2, 56.2′, L₂) comprises a free-form-surface/prism lens (56.2,L₂, 128).

In accordance with one set of embodiments of the second aspect 10.2 ofthe near-eye display system (10, 10.2), the controllable light source(97) may incorporate a flat-panel two-dimensional light light-sourcearray (98) of light-source elements (100, 100′, 100″), wherein the exitpupil (18) is formed as the exit-pupil image (18′) by the seconddioptric-power optical element (56, 56.2, 56.2′, L₂), and the exit pupil(18) is substantially planar, wherein each light-source element (100,100′, 100″) of the flat-panel two-dimensional light light-source array(98) of the light-source elements (100, 100′, 100″) may incorporate alight-emitting-diode element (100′).

In accordance with one set of embodiments of the third aspect 10.3 ofthe near-eye display system (10, 10.3), the controllable light source(97) incorporates a curved two-dimensional light light-source array(106) of light-source elements (100, 100′, 100″), the exit pupil (18) isformed as the exit-pupil image (18′) by the second dioptric-poweroptical element (56, 56.2, 56.2′, L₂), and the exit pupil (18) iscurved, wherein each light-source element (100, 100′, 100″) of thecurved two-dimensional light light-source array (106) of thelight-source elements (100, 100′, 100″) may incorporate either alight-emitting-diode element (100′) located on an underlyingconcave-curved surface (107), or a first end of a correspondingfiber-optic light pipe supported from an underlying concave-curvedsurface (107), with each second end of the corresponding fiber-opticlight pipe is illuminated by a corresponding light-emitting-diodeelement, wherein the corresponding light-emitting-diode element may beincorporated in a flat-panel light-source array. In one set ofembodiments, a curvature of the exit pupil (18) substantially conformsto a curvature of a front surface (20′) of the eye (20).

In accordance with one set of embodiments of the fourth aspect 10.4 ofthe near-eye display system (10, 10.4), the controllable light source(97) incorporates a curved light-redirecting surface (110) incooperation with a modulated scanned beam of light (112), the exit pupil(18) is formed as the exit-pupil image (18′) by the seconddioptric-power optical element (56, 56.2, 56.2′, L₂), and the exit pupil(18) is curved, wherein the curved light-redirecting surface (110) mayincorporate at least one optical surface selected from the groupconsisting of a light-scattering surface, a holographic surface, and adiffractive surface. The fourth aspect 10.4 of the near-eye displaysystem (10, 10.4) may further incorporate: a) light-beam source (118),wherein the light-beam source (118) provides for generating the beam oflight (114), and provides for modulating an intensity thereof responsiveto an light-beam-magnitude subpupil modulation control signal (51′); b)a light-beam-directing element (120), wherein the light-beam-directingelement (120) provides for directing the beam of light (114) onto thecurved light-redirecting surface (110) at a location thereon responsiveto an angular orientation of the light-beam-directing element (120); andc) a light-beam scanner (116), wherein the light-beam scanner (116)provides for controlling the angular orientation of thelight-beam-directing element (120), the light-beam scanner (116) and thelight-beam source (118) are controlled over time responsive to alight-beam-position subpupil modulation control signal (51″) from asubpupil modulation controller (50) so as to provide for generating themodulated scanned beam of light (112), and so as to provide for scanningthe modulated scanned beam of light (112) over a region (122) of thecurved light-redirecting surface (110) so as to form a corresponding atleast one subpupil (32), wherein the light-beam-directing element (120)may incorporate at least one optical element selected from the groupconsisting of a mirror, a holographic element, and a diffractiveelement. The fourth aspect 10.4 of the near-eye display system (10,10.4) may further incorporate: a) an eye-tracking subsystem (42),wherein the eye-tracking subsystem (42) provides at least a measure of alocation of an eye pupil (38) of the eye (20); and b) the subpupilmodulation controller (50), wherein the subpupil modulation controller(50) provides for controlling an activation state of each of at leastone subpupil (32) of the subpupil modulator (30, 30.4) responsive atleast to the measure of the location of the eye pupil (38) of the eye(20). In one set of embodiments, a curvature of the exit pupil (18)substantially conforms to a curvature of a front surface (20′) of theeye (20).

In accordance with one set of embodiments of third 10.3 and fourth 10.4aspects of the near-eye display system (10, 10.3, 10.4), the subpupilmodulator (30, 30.3, 30.4) incorporates at least one modulation element(90) located on or in cooperation with an associated modulation surface(92, 92″), the associated modulation surface (92, 92″) is curved, and anassociated curved subpupil image 126 of the associated modulationsurface (92, 92″) is located on a corresponding curved subpupil surface(84, 84″), wherein a curvature of the curved subpupil surface (84, 84″)may substantially conform to a curvature of a front surface (20′) of theeye (20).

Generally, in accordance with one set of embodiments, a near-eye displaysystem (10, 10.1, 10.2, 10.3, 10.4) for providing an image (16′″) of anobject (52, 94, 16) for viewing by an eye (20) of a user (22)incorporates a) a geometric surface (18″, 84, 84′, 84″) having one ormore first locations at which rays of light (16′) from an entirely of animage (16) intersect; b) a physical surface (92, 92′, 92″) having one ormore second locations at which the rays of light (16′) from an entirelyof the image (16) intersect; c) a light-limiting means (30; 30.1 58;30.2, 98; 30.3, 106; 30.4, 110, 112, 114, 116, 118) for independentlylimiting the rays of light (16′) emitted from or passing through the oneor more second locations; and d) an optical system (14, 14.1, 14.2,14.2′, 14.2″, 14.2′″) the provides for forming the geometric surface(18″, 84, 84′, 84″) as a real image of the physical surface (92, 92′,92″). The near-eye display system (10, 10.1, 10.2, 10.3, 10.4) may alsoincorporate a) a means (42, 44, 46, 48) for detecting at least thelocation of an eye pupil (38) of the eye (20) with respect to thegeometric surface (18″, 84, 84′, 84″); and b) a control system (50) forelectronically controlling the light-limiting means (30; 30.1 58; 30.2,98; 30.3, 106; 30.4, 110, 112, 114, 116, 118) so that the light (16′)passing through at least some of the first locations is as leastpartially limited. The physical surface (92, 92′, 92″) may be eithersubstantially planar (92′) or curved (92″).

Referring again to FIGS. 16, 17, 44, and 53, in one set of embodimentsof the second 10.2 and fifth 10.5 aspect near-eye display systems 10,the associated flat-panel two-dimensional light-source array 98 isimplemented with a two-dimensional array 26 of associated light-sourceelements 100 similar to that used as the image generator 12, 12.1 of thefirst aspect near-eye display system 10, 10.1, but with each associatedlight-source element 100—for example, with each light-source element100, 100′/light-emitting image-display pixel 54 comprising an associatedset of red (R), green (G) and blue (B) light-emitting-diodes—operated ina white-light mode of operation, so as to provide for effectively actingas white-light light-source elements 100. Similarly, referring to FIGS.18, 19, 45 and 47, in one set of embodiments of the third aspectnear-eye display system 10, 10.3, each associated light-source element100, 100′ comprises an associated set of red (R), green (G) and blue (B)light-emitting-diodes, similarly operated in a white-light mode ofoperation. For example, in accordance with a first white-light mode ofoperation, if the flat-panel two-dimensional light-source array 98comprises an array of spatially separate color componentlight-modulating pixels, for example red (R), green (G) and blue (B), inclusters—for example, with each pixel having a color filter to generateits respective color—then the separate color component light-modulatingpixels would be operated simultaneously at associated relativeintensities sufficient to effectively generate what is perceived to bewhite light. As a second example, in accordance with a secondwhite-light mode of operation, if the flat-panel two-dimensionallight-source array 98 comprises an array of light-modulating pixels thatoperate in a field-sequential mode where full images of fields of singlecolor components of an image are displayed so that the eye perceives thecomposite image in full color due to persistence, then each associatedlight-source element 100, 100′ would generate individual colorssequentially at associated relative intensities sufficient to so as tobe perceived to be white light. Similarly, referring again to FIGS. 18,19, 45 and 47, in one set of embodiments of the third aspect near-eyedisplay system 10, 10.3, each associated light-source element 100, 100′comprises an associated set of red (R), green (G) and blue (B)light-emitting-diodes, similarly operated in a white-light mode ofoperation, supra.

The associated optical subsystems 14, 14.1, 14.2, 14.3, 14.4, 14.5,14.6, 14.7 provide for a one-to-one correspondence between modulatedsubpupils 32′ of the associated subpupil modulator 30, 30.1, 30.2, 30.3,30.4, 30.5 within the associated aperture stop 28 of the associatedoptical subsystems 14, 14.1, 14.2, 14.3, 14.4, 14.5, 14.6, 14.7 andcorresponding exit subpupils 32 within the exit pupil 18. Each point onthe aperture stop 28 is imaged to a corresponding point in the exitpupil 18, i.e. with a one-to-one relationship between points in “objectspace” of the aperture stop 28/subpupil modulator 30, 30.1, 30.2, 30.3,30.4, 30.5, to corresponding points in “image space” of the surface 18″of the exit pupil 18, and for each of the associated exit subpupils 32associated with corresponding modulated subpupils 32′ that are formed bythe subpupil modulator 30.

Referring to FIGS. 59a and 59b , under associated ideal conditions andconfigurations, the associated optical subsystems 14, 14.1, 14.2, 14.3,14.4, 14.5, 14.6, 14.7, also provide for a one-to-one correspondencebetween modulated subpupils 32′ of the associated subpupil modulator 30,30.1, 30.2, 30.3, 30.4, 30.5 and corresponding regions within the exitpupil 18, i.e. so that the resulting exit subpupils 32 are distinct andseparated from one another, i.e. non-overlapping within the exit pupil18. For example, referring to FIG. 59a , the hypothetical intensityprofile of light 104 through the center of an activated modulatedsubpupil 32′—e.g. a light-modulating pixel 60 of a flat-paneltwo-dimensional modulation array 58 of the first aspect near-eye displaysystem 10, 10.1, or a light-source element 100 of the second 10.2through fifth 10.5 aspect near-eye display systems 10—of the subpupilmodulator 30, 30.1, 30.2, 30.3, 30.4, 30.5 within the associatedaperture stop 28 of an associated optical subsystem 14, 14.1, 14.2,14.3, 14.4, 14.5, 14.6, 14.7 comprises a uniform non-zero level acrossthe lateral extent thereof, and a zero level outside the lateral extentthereof. Referring to FIG. 59b , the optical subsystem 14, 14.1, 14.2,14.3, 14.4, 14.5, 14.6, 14.7 collects the light 16′ of the modulatedsubpupil 32′ and forms therefrom an associated exit subpupil 32 withinthe associated exit pupil 18.

In accordance with one set of embodiments, the optical subsystem 14,14.1, 14.2, 14.3, 14.4, 14.5, 14.6, 14.7 forms on the surface 18″ of theexit pupil 18 a real image of the subpupil modulator 30, 30.1, 30.2,30.3, 30.4, 30.5, with the boundary of the exit pupil 18 correspondingto the corresponding boundary of the aperture stop 28 of the opticalsubsystem 14, 14.1, 14.2, 14.3, 14.4, 14.5, 14.6, 14.7. With the exitpupil 18 located proximate to the outer surface, i.e. the front surface20′, of the eye 20, this a) provides for enabling the user 22 tosee—without vignetting—the full extent of the virtual image 16′″ fromeither the flat-panel two-dimensional image-display array 52 or theflat-panel two-dimensional image-display modulation array 94 over a fullrange of rotation of the eye 20, and b) provides for minimizing the sizeof the associated exit subpupils 32.

For the first aspect near-eye display system 10, 10.1, each modulatedsubpupil 32′ of the subpupil modulator 30, 30.1 receives light from theentirety of the flat-panel two-dimensional image-display array 52, andfor the second 10.2 through fifth 10.5 aspect near-eye display systems10, light 16′ from each light-source element 100 of the associatedsubpupil modulator 30, 30.2, 30.3, 30.4, 30.5 illuminates the entiretyof the associated flat-panel two-dimensional image-display modulationarray 94. Accordingly, in both cases, each associated modulated subpupil32′ contains light 16′ of the entirety of the associated virtual image16′″, and the associated optical subsystem 14, 14.1, 14.2, 14.3, 14.4,14.5, 14.6, 14.7 generally provides for collecting the light 16′ of thevirtual image 16′″ propagating from the aperture stop 28 of the opticalsubsystem 14, 14.1, 14.2, 14.3, 14.4, 14.5, 14.6, 14.7 onto theassociated exit pupil 18 on a surface 18″ proximate to an outer surface20′ of the eye 20, and, as a result of the source 52, 94 of the virtualimage 16′″ being flat, with each resulting exit subpupil 32 presentingsubstantially the same virtual image 16′″.

During operation of the near-eye display system 10, only a subset of themodulated subpupils 32′ of the subpupil modulator 30 are activated atany given time, so that at any given time, the aperture stop 28 is notfully illuminated. The maximum extent (i.e. the size) of the exit pupil18 will depend upon the manner by which the optical subsystem 14, 14.1,14.2, 14.3, 14.4, 14.5, 14.6, 14.7 forms the associated exit-pupil image18′, i.e. the degree to which the exit-pupil image 18′ is a focused realimage of the subpupil modulator 30 within the associated aperture stop28. However, with the aperture stop 28 not fully illuminated at anygiven time, the outer boundary of the resulting associated exit-pupilimage 18′ will not correspond to that of the aperture stop 28.Accordingly, the outer boundary of the exit pupil 18/exit-pupil image18′ is delineated with phantom lines in FIGS. 5, 7, 11, 13, 15, 22, 24,26, 28, 30, 35, 37, 39, 41, and 43 so as to illustrate that theeffective aperture of the optical subsystem 14, 14.1, 14.2, 14.3, 14.4,14.5, 14.6, 14.7 is defined/limited by the associated subpupil modulator30, either as a physical “sub-aperture” defined either by thelight-restricting, “hard” boundaries of “open” light-modulating pixels60 (acting as “shutters) of a flat-panel two-dimensional modulationarray 58 of a first-aspect subpupil modulator 30, 30.1, or bylight-limiting “soft” boundaries of activated light-source elements 100of a controllable light source 97 of a remaining-aspect subpupilmodulator 30, 30.2, 30.3, 30.4, 30.5. Furthermore, thespatially-discrete nature of the modulated subpupils 32′ of the subpupilmodulator 30, 30.1 30.2, 30.3, 30.4, 30.5, i.e. withpermanently-deactivated gaps between the modulated subpupils 32′, theresulting structure will typically be unnoticeable (much like viewing adistant image through a window screen positioned relatively close to theeye), but a perception of this structure can otherwise be mitigated byuse of depixelation optics if the associated modulation structure is nototherwise blurred by inherent realistic limitations of the associatedoptical subsystem 14, 14.1, 14.2, 14.3, 14.4, 14.5, 14.6, 14.7.

Accordingly, the optical subsystem 14, 14.1, 14.2, 14.3, 14.4, 14.5,14.6, 14.7 provides for projecting light 16′ of a virtual image 16″ theeye 20 of a user 22, wherein modulated subpupils 32′ located on aphysical modulation surface 92 of a subpupil modulator 30 within theoptical subsystem 14, 14.1, 14.2, 14.3, 14.4, 14.5, 14.6, 14.7 at leasteither partially block a portion of that light 16′, or prevent thatportion of light 16′ from being generated, so as to prevent that portionof light 16′ from entering the eye pupil 38 of the eye 20 of the user22. In accordance with one set of embodiments, which provide for therelatively smallest associated exit subpupils 32, the exit-pupil image18′ is formed proximate to the front surface 20′ of the eye 20 as a realimage of the modulation surface 92. Alternatively, the exit-pupil image18′ formed proximate to the front surface 20′ of the eye 20 may be animage of the modulation surface 92, albeit a poorly-formed image, whilestill providing for collecting the light 16′ from the modulation surface92 into the exit pupil 18. Accordingly, as used herein, an image of themodulation surface 92 is defined as the spatial distribution of light16′ that has passed through, or has emanated from, that modulationsurface 92 and has exited the optical subsystem 14, 14.1, 14.2, 14.3,14.4, 14.5, 14.6, 14.7 to form a surface 18″—also referred to herein asan exit pupil 18—within the volumetric visual environment (VVE) 80 ofthe optical subsystem 14, 14.1, 14.2, 14.3, 14.4, 14.5, 14.6, 14.7,wherein the portion of that light 16′ passing through, or emanatingfrom, any particular location on that modulation surface 92 passesthrough less than the entirety of that exit pupil 18.

Referring to FIGS. 59c and 60, in accordance with a non-ideal opticalsubsystem 14, 14.1, 14.2, 14.3, 14.4, 14.5, 14.6, 14.7, for example, onesubject to practical constraints on the nature, construction and imagingproperties of the associated dioptric-power optical elements 56, 56.1,56.2, 56.3, and associated constraints on the layout of an associatedpractical, commercially-viable near-eye display system 10—wherein theassociated imaging properties of the associated dioptric-power opticalelements 56, 56.1, 56.2, 56.3 might be relaxed in favor of eitherrelatively-simpler optics or a relatively-more-compact optical subsystem14, 14.1, 14.2, 14.3, 14.4, 14.5, 14.6, 14.7, —a resulting correspondingintensity distribution of an associated resulting realized exit subpupil32″ might become laterally expanded beyond the nominal ideal boundaries162 of a corresponding idealized exit subpupil 32, so that an ensembleof realized exit subpupils 32″ might then overlap one another within theexit pupil 18, resulting in a prospective violation of one-to-onecorrespondence between regions within the exit pupil 18 andcorresponding modulated subpupils 32′, notwithstanding the resultingexit subpupils 32, 32″ within the exit pupil 18 remaining in one-to-onecorrespondence with corresponding modulated subpupils 32′ of thesubpupil modulator 30. Furthermore, relative to a counterpart idealizedexit subpupil 32, in addition to overlapping with other realized exitsubpupil 32″, a corresponding realized exit subpupil 32″ mightprospectively be relatively blurry and of non-uniform size or shape. Forexample, an expansion in the lateral extent of the realized exitsubpupil 32″ relative to that of an idealized exit subpupil 32 can becaused by a lack of concentricity of the eye pupil 38 and associatedfront surface 20′ of the eye 20 with respect to the surface 18″ of theexit pupil 18, or a misalignment of the near-eye display system 10 withrespect to the eye 20 of the user 22. Accordingly, for any particularpoint on the eye pupil 38, there is a prospect for that point to receivelight 16′ from a plurality of different modulated subpupils 32′.

For example, FIG. 60 illustrates a plan view of an exit pupil 18 of anear-eye display system 10, the latter of which incorporate an opticalsubsystem 14, 14.2, 14.3, 14.4, 14.5, 14.6, 14.7 that provides forforming a virtual image 16′″ of a flat-panel two-dimensionalimage-display modulation array 94 illuminated by a subpupil modulator 30comprising a controllable light source 97 incorporating a plurality ofassociated light-source elements 100, and that provides for collectingat least a portion of the light 16′ that propagates from eachlight-source element 100 through the flat-panel two-dimensionalimage-display modulation array 94, with light 16′ from each light-sourceelement 100 forming an associated realized exit subpupil 32″ on thesurface 18″ of the exit pupil 18, wherein as a result of the nature ofthe optical subsystem 14, 14.2, 14.3, 14.4, 14.5, 14.6, 14.7 and theshape and location of the surface 18″ of the exit pupil 18 in relationto that of the front surface 20′ of the eye 20, the lateral extent of atleast some of the realized exit subpupils 32″ are expanded relative towhat would have been corresponding idealized exit subpupils 32, so thatat least some adjacent realized exit subpupils 32″ overlap one anotherby at least twenty (20) percent. Accordingly, the resulting plurality ofrealized exit subpupils 32″ create, and when activated, fill, theassociated exit pupil 18 with an array of similar butspatially-distinct, incompletely-overlapping realized exit subpupils32″. Accordingly, each realized exit subpupil 32″, although generatedby, is not necessarily a well-formed image of, a correspondinglight-source element 100, and the controllable light source 97/subpupilmodulator 30 is not necessarily a corresponding well-formed entrancepupil 28′ of the optical subsystem 14, 14.2, 14.3, 14.4, 14.5, 14.6,14.7.

Responsive to the determination by the eye-tracking subsystem 42 of alocation and extent of the eye pupil 38, the subpupil modulationcontroller 50 provides for deactivating modulated subpupils 32′associated with exit subpupils 32 that are either outside the associatedActive Subpupil Region (ASR) 72, or that do not even partially overlapthe eye pupil 38, which provides for reducing the reflection ofextraneous light 16 ^(iv) from the front surface 20′ of the eye 20, andwhich, for a near-eye display system 10, 10.2, 10.3, 10.4, 10.5incorporating a controllable light source 97, provides for reducingpower consumed by the controllable light source 97. However, forrelatively-expanded realized exit subpupils 32″, relatively tocounterpart idealized exit subpupils 32. a relatively-higher number ofrealized exit subpupils 32″ would prospectively at least-partiallyoverlap the eye pupil 38, thereby expanding the associated correspondingeffective Active Subpupil Region (ASR) 72′, so that under thisrelatively-simple subpupil control strategy, —i.e. in accordance witheither the first-aspect 70.1 or second-aspect subpupil modulation scheme70, supra—relatively-fewer associated modulated subpupils 32′ could bedeactivated without impacting perception of the virtual image 16′″ beingviewed by the user 22.

Referring to FIG. 61, a first aspect of a subpupil modulation controlprocess 6100 for controlling a subpupil modulator 30 provides foractivating a single modulated subpupil 32′ most closely associated witha central location of an eye pupil 38 of an eye 20 at a viewing locationproximate to the exit pupil 18 within the volumetric visual environment(VVE) 80, wherein, in step (6102), the subpupil modulation controller 50receives from the eye-tracking subsystem 42 a measure of a centrallocation—for example, the center-of-area—of the eye pupil 38. Then, instep (6104), the subpupil modulation controller 50 identifies the exitsubpupil 32 that is closest to that central location of the eye pupil32, and identifies the associated modulated subpupil 32′ thatcorresponds to that eye pupil 32, or alternatively, directly from atable lookup of a two-dimensional table that provides the identity ofthe corresponding modulated subpupil 32′ as a function of transverse X-and Y-locations within the exit pupil 18 of boundaries of regionsilluminated by the corresponding exit subpupils 32, 32″, responsive tothe measure from the eye-tracking subsystem 42 of the central locationof the eye pupil 38. The subpupil modulation controller 50 thenactivates the resulting identified modulated subpupil 32′, and, in step(6106), deactivates the remaining modulated subpupils 32′. In accordancewith one aspect, optional step (6108) provides for the intensity of thesingle light-source element 100, 90 associated with the single activemodulated subpupil 32′ to be adjusted responsive to input from the user22 so as to provide for adjusting the level of brightness of theassociated virtual image 16′″ to the preference of the user 22. For exitsubpupils 32 that are smaller in diameter than the opening of the eyepupil 38, the first-aspect subpupil modulation control process 6100provides for implementing an embodiment of the third aspect subpupilmodulation scheme 70, 70.3, supra.

Notwithstanding the prospect of activating and viewing only a singleexit subpupil 32, 32″ at a time, and the associated benefit of minimalpower usage and lack of, or mitigation against, vignetting, asimultaneous activation of more than one exit subpupil 32, 32″ also canbe beneficial for the following three reasons. First, a singlelight-source element 100 might be naturally limited in intensity,whereas multiple light-source elements 100 can share the burden andassure that the overall perceived image brightness is relativelyconstant, independent of gaze direction 34. Second, it may bechallenging to track the eye pupil 38 sufficiently accurately, orsufficiently fast, to provide for activating the light-source element100 from which light 16′ generated thereby would pass through the eyepupil 38, whereas a plurality of simultaneously-activated exit subpupils32, 32″ associated with a relatively-larger Active Subpupil Region (ASR)72 could help assure that the overall perceived image brightness isrelatively constant, independent of gaze direction 34. Third, andfinally, a single light-source element 100, especially if very small,results in a relatively-large depth of focus, which not only can revealstructures or contaminants of the optical subsystem 14, 14.2, 14.3,14.4, 14.5, 14.6, 14.7 located away from the flat-panel two-dimensionalimage-display modulation array 94, but, if sufficiently small, couldprovide for revealing adverse effects of diffraction or interferencethat might otherwise detract from a desired naturally appearing virtualimage 16′″ of the flat-panel two-dimensional image-display modulationarray 94.

Notwithstanding the benefit of relatively small, non-overlappingidealized exit subpupil 32 in order to provide for prospectivelydeactivating the most possible associated light-source elements 100, andthereby minimizing associated power usage, it should be understood thatthe exit subpupils 32 need not necessarily be of similar size or shape,nor non-overlapping with respect to one another, nor necessarilywell-formed images of the corresponding light-source elements100/modulated subpupils 32′, which provides for significantly relaxingthe requirements of the design of the associated optical subsystem 14,14.2, 14.3, 14.4, 14.5, 14.6, 14.7. Instead, for a realized exitsubpupil 32″ of arbitrary size, shape and image quality, in accordancewith second through fourth aspects of associated subpupil modulationcontrol processes, infra, the subpupil modulation controller 50 incooperation with the eye-tracking subsystem 42 provides for furthercontrolling the modulated subpupils 32′ for which the correspondingassociated realized exit subpupils 32″ at least partially overlap theeye pupil 38, so as to provide for reducing power usage and possibly thereflection of extraneous light 16 ^(iv) from the front surface 20′ ofthe eye 20. In accordance with one aspect, this is provided for by firstestablishing a predetermined mapping, for each light-source element100/modulated subpupil 32′, of the location lateral extent (e.g. shapeand size), and intensity profile of each corresponding realized exitsubpupil 32″. In view of the intensity of the light 16′ passing througheach exit subpupil 32, 32″ not likely being uniform thereacross, theintensity profile of the associated exit subpupil 32, 32″ can be used toadjust/optimize the intensities of the active exit subpupils 32, 32″ soas to provide for a beneficial/optimal overall intensity profile withinthe associated Active Subpupil Region (ASR) 72, to not only maintain auniform perceived brightness as the eye pupil 38 scans through differentgaze directions 34, but also, to the extent possible, to concentrate thelight 16′ through the center of the eye pupil for best perceived qualityof the virtual image 16′″.

More particularly, referring to FIG. 62, an associated subpupil mappingprocess commences, in step (6202), with the selection of a modulatedsubpupil 32′/light-source element 100 of the of the plurality ofmodulated subpupils 32′/light-source elements 100 of the subpupilmodulator 30. Then, in step (6204), the selected modulated subpupil32′/light-source element 100 is activated—either actually in cooperationwith the hardware of an associated near-eye display system 10, or bysimulation—to provide for illuminating, or simulating the illuminationof, an associated exit pupil 18, so as to generate an associated exitsubpupil 32, 32″ therewithin. Then, the location, lateral extent (e.g.size and shape), and intensity profile of the illuminated exit subpupil32, 32″ are determined in step (6206), and, in step (6208), stored forfuture use, for example, in an exit-subpupil characterization table 164,after which, from step (6210), the next modulated subpupil32′/light-source element 100 is selected in step (6212), and the processof steps (6202) through (6212) is repeated until all of the modulatedsubpupils 32′/light-source element 100 have been processed, after which,from step (6210), the mapping process is complete in step (6214), withthe locations, lateral extents, and intensity profiles of all the exitsubpupils 32, 32″ having been determined and stored for future use.Accordingly, for a particular viewing direction and opening of the eyepupil 38, and a resulting particular area within the exit pupil 18occupied by the eye pupil 38, the exit-subpupil characterization table164 provides for identifying those exit subpupils 32, 32″ that overlapwith that area; and for each such exit subpupil 32, 32″, the relativeamount of light within that overlapping area, relative to the totalamount of light of that exit subpupil 32, 32″, and the identity of thecorresponding associated modulated subpupil 32′/light-source element.

Referring to FIG. 63, a second aspect of a subpupil modulation controlprocess for controlling a subpupil modulator 30 provides for controllingactivation of exit subpupils 32, 32″ responsive to the degree of overlapthereof with an eye pupil 38, commencing, in step (6302), withreceipt—from the eye-tracking processor 48 of the eye-tracking subsystem42—of measures of the location and lateral extent (e.g. size and shape)of the eye pupil 38. Then, in step (6304), using the exit-subpupilcharacterization table 164 determined by the subpupil mapping process6200, supra, the subpupil modulator 30 identifies the subset of exitsubpupils 32, 32″ that are proximate to the location of the eye pupil38, for example exit subpupils 32, 32″ either that are within, or thatat least in part overlap, the eye pupil 38.

For example, referring to FIGS. 60 and 64, —the latter representing anintensity profile of the former through the center of the eye pupil 38,—the set of exit subpupils 32, 32″ labeled as “A”, “B”, or “C” areidentified as being proximate to the eye pupil 38 as a result of each ofthese exit subpupils 32, 32″ either being entirely within (i.e. “A”), orintersecting (i.e. “B” and “C”) the boundary of the eye pupil 38. Eachof the exit subpupils 32, 32″, except for the central exit subpupil 32labeled as “A”, is illustrated in FIG. 60 with a pair of inner and outerconcentric circles, with the inner circle representing the extent of acorresponding idealized exit subpupil 32, and the outer circlerepresenting the extent of the corresponding realized exit subpupil 32″.The Active Subpupil Region (ASR) 72 associated with the idealized exitsubpupils 32 entirely encircles all of the exit subpupils 32 labeled as“A”, “B”, “C”, “D”, or “E”, whereas a relatively-expanded ActiveSubpupil Region (ASR) 72′ is needed to encircle the correspondingassociated realized exit subpupil 32″, thereby involving a relativelarger proportion of the area of the exit pupil 18.

Returning to FIG. 63, in step (6306), the remaining exit subpupils 32,32″ that are not proximate to the eye pupil 38—for example, entirelyoutside the boundary of the eye pupil 38—are deactivated to conservepower and reduce the reflection of extraneous light 10. For example, asillustrated in FIG. 64, the exit subpupils 32, 32″ labeled “D” or “E”are deactivated. Then, beginning with step (6308), for each exitsubpupil 32, 32″ that was identified from step (6304) as being proximateto the eye pupil 38, in step (6310), using the exit-subpupilcharacterization table 164 determined by the subpupil mapping process6200, supra, the subpupil modulator 30 determines the relative amount ofthe exit subpupil 32, 32″ that is within the eye pupil 38, for example,either the relative area or, based upon the associated intensityprofile, the relative amount of light. Then, in step (6312), if asubstantial portion of the exit subpupil 32, 32″ is located outside theeye pupil 38, for example, at least 80 percent, then, in step (6314),the modulated subpupil 32′ associated with that exit subpupil 32, 32″ isdeactivated. Otherwise, from step (6312), if a substantial portion ofthe exit subpupil 32, 32″ is not located outside the eye pupil 38, then,in step (6316), the modulated subpupil 32′ associated with that exitsubpupil 32, 32″ is activated. Then, following either of steps (6314) or(6316), if all of the exit subpupils 32, 32″ identified in step (6304)as being proximate to the eye pupil 38 have not been processed, thensteps (6308) through (6314)/(6316) are repeated for the next exitsubpupil 32, 32″ that is selected in step (6320). Then, from step(6318), after all of the relatively-proximate exit subpupils 32, 32″have been processed, in step (6324), the intensities of the light-sourceelements 100 of the modulated subpupils 32′ associated with the exitsubpupils 32, 32″ that had been activated in step (6316) are adjusted,possible with input, in step (6326), from the user 22 in respect of theoverall brightness of the perceived associated virtual image 16′″.Following step (6324), the subpupil modulation control process 6300repeats beginning with step (6302), so as to provide for continuouslytracking and responding to the location and extent of the eye pupil 38.

For example, referring also to FIG. 65, as a result of a substantialportion of the exit subpupils 32, 32″ labeled “C” in FIGS. 60 and 64being outside the eye pupil 38, in step (6314), the “C”-labeled exitsubpupils 32, 32″ are deactivated, and, in step (6324), the intensity ofmodulated subpupils 32′/light-source elements 100 associated with the“B”-labeled exit subpupils 32, 32″ is increased so as to maintain theoverall brightness of the virtual image 16′″. Alternatively, oradditionally, the overall brightness of the virtual image 16′″ could bemaintained by increasing the intensity of the modulated subpupil32′/light-source element 100 associated with the “A”-labeled exitsubpupils 32, 32″. Absent the intensity adjustment in step (6324), theoverall brightness of the virtual image 16′″ would otherwise be loweredrelative to that of the virtual image 16′″ prior to the deactivation ofthe “C”-labeled exit subpupils 32, 32″ in step (6314). The deactivation,in step (6314), of exit subpupils 32, 32″ in cooperation the adjustment,in step (6324), of the intensity of remaining, activated exit subpupils32, 32″ provides for more efficient power usage than without the actionsof steps (6314) and (6324), with the added benefit of a reduction inreflected extraneous light 16 ^(iv).

In accordance with the first-aspect near-eye display system 10, 10.1,each point on the subpupil modulator 30, 30.1/flat-panel two-dimensionalmodulation array 58, and therefore, each associated modulated subpupil32′, is illuminated by the entirety of the associated flat-paneltwo-dimensional image-display array 52. In accordance with thesecond—10.2 through fifth—10.5 aspect near-eye display systems 10, 10.2,10.3, 10.4, 10.5, light 104 from each modulated subpupil 32′ generatedby the associated controllable light source 97 of an associated subpupilmodulator 30, 30.2, 30.3, 30.4, 30.5 illuminates the entirety of theassociated flat-panel two-dimensional image-display modulation array 94.Accordingly, each exit subpupil 32, 32″ that is generated by acorresponding associated modulated subpupil 32′ contains the entirety ofthe image content of the virtual image 16′″, so that the full imagecontent of the virtual image 16′″ is viewable by the user 22 with anyactivated exit subpupil 32, 32″, regardless of the gaze direction 34 ofthe eye pupil 38. Accordingly, although a deactivation of one or moreexit subpupils 32, 32″ overlapping the eye pupil 38, absent a change inintensity of the remaining exit subpupils 32, 32″, would simply causethe virtual image 16′″ to be dimmer, the apparent brightness of thevirtual image 16′″ can be maintained by the subpupil modulationcontroller 50 by maintaining the composite intensity of the remaining,activated exit subpupils 32, 32″.

Referring to FIG. 66, a third aspect of a subpupil modulation controlprocess 6600 for controlling a subpupil modulator 30 also provides forcontrolling activation of exit subpupils 32, 32″ responsive to thedegree of overlap thereof with an eye pupil 38, and is the same as thesecond-aspect subpupil modulation control process 6300, supra, exceptthat steps (6310) through (6316), (6324) and (6326) are replaced bysteps (6602) and (6604), wherein, following step (6308), for each exitsubpupil 32, 32″ proximate to the eye pupil 38, in step (6602), thesubpupil modulation controller 50 adjusts the intensity thereof—e.g. byadjusting the intensity of the corresponding associated modulatedsubpupil 32′/light-source element 100—in accordance with apredetermined, stored exit-subpupil intensity-control table 166 thatprovides the intensity of the associated modulated subpupil32′/light-source element 100 as a function of the measures from step(6302) of location and extent of eye pupil 38, so as to provide for aprospective optimal level of intensity of the modulated subpupil32′/light-source element 100 to the satisfaction of most users 22. Forexample, in accordance with one aspect, the exit-subpupilintensity-control table 166 is predetermined by simulating thesecond-aspect subpupil modulation control process 6300, supra, for arange of possible locations and extents of the eye pupil 38, andrecording, as a function of the locations and extents of the eye pupil38, the resulting intensity levels of the associated modulated subpupils32′/light-source elements 100 that are determined thereby responsive tothe associated exit-subpupil characterization table 164. In accordancewith one set of embodiments, the exit-subpupil intensity-control table166 contains a set of intensity factors that are used to multiply acorresponding predetermined, stored nominal intensity levels modulatedsubpupils 32′/light-source elements 100. Similar to the second-aspectsubpupil modulation control process 6300, supra, the intensities of themodulated subpupils 32′/light-source elements 100 from the associatedexit-subpupil intensity-control table 166 may be adjusted responsive toinput from a particular user 22 in step (6604) so as to provide for adesired level of overall brightness of the perceived associated virtualimage 16′″.

Referring to FIG. 67, a fourth aspect of a subpupil modulation controlprocess for controlling a subpupil modulator 30 also provides forcontrolling activation of exit subpupils 32, 32″ responsive to thedegree of overlap thereof with an eye pupil 38, and is the same as thethird-aspect subpupil modulation control process 6600, supra, exceptthat steps (6304) through (6320), (6602) and (6604) are replaced bysteps (6702) through and (6706), wherein, following step (6302), for aparticular set of measures of the location and lateral extent of the eyepupil 38 from the eye-tracking subsystem 42, in step (6702), thesubpupil modulation controller 50 determines the intensity controlvalues of each element of a global subpupil intensity control array 168,the elements of which are in one-to-one correspondence with themodulated subpupils 32′/light-source elements 100, 90 of the associatedsubpupil modulator 30, 30.2, 30.3, 30.4, 30.5, the values of which canrange from OFF or zero for a corresponding deactivated exit subpupil 32,32″ to a maximum level corresponding to a maximum level of intensity ofthe associated modulated subpupil 32′/light-source element 100, 90, andinclude levels therebetween (either continuous or discrete) less thanthe maximum level of intensity so as to provide for intermediate levelsof intensity of the associated modulated subpupil 32′/light-sourceelement 100, 90. For example, in accordance with one set of embodiments,the levels of intensity of the elements of the global subpupil intensitycontrol array 168 are the same, or at least substantially the same, aswhat would be provided for by either the second—or third-aspect subpupilmodulation control processes 6300, 6600, supra, possibly limited to thedetermination for exit subpupil 32, 32″ within the associated ActiveSubpupil Region (ASR) 72, with the remaining exit subpupils 32, 32″deactivated, thereby precluding the need to determine in real time whichexit subpupils 32, 32″ are outside of the Active Subpupil Region (ASR)72 unless the Active Subpupil Region (ASR) 72 is being modified in realtime, for example, when compensating for rapid eye movements. Inaccordance with one set of embodiments, the predetermined intensityvalues of the exit-subpupil intensity-control table 166 provide for aconsistent perceived brightness of the virtual image 16′″ whilemaximizing power efficiency, for example, by maximizing the number ofmodulated subpupils 32′ that are deactivated.

In accordance with one aspect, the values of the elements of the globalsubpupil intensity control array 168 are determined responsive to themeasures of the location and lateral extent of the eye pupil 38 from theeye-tracking subsystem 42, provided from step (6302), for example, usingthe third-aspect subpupil modulation control process 6600, with theassociated values of the exit-subpupil intensity-control table 166predetermined—either by simulation or measurement—for a range ofpossible values of the measures of the location and lateral extent ofthe eye pupil 38, for each of the possible exit subpupils 32, 32″ withinthe exit pupil 18, and associated with the complete set of modulatedsubpupils 32′ of the subpupil modulator 30, 30.2, 30.3, 30.4, 30.5. Inaccordance with one aspect in cooperation with a predeterminedexit-subpupil intensity-control table 166 covering the range of possibleconditions of the eye pupil 38, the intensity values of the elements ofthe global subpupil intensity control array 168 are provided for by atable-lookup process by which the intensity value of each exit subpupil32, 32″—ranging from deactivated to maximum intensity, and intensitylevels therebetween—is determined for each of the exit subpupils 32, 32″by a table lookup of the exit-subpupil intensity-control table 166responsive to the location and extent of the eye pupil 38. Following thedetermination in step (6702) of the intensity control levels of theglobal subpupil intensity control array 168, in step (6704), each of thecorresponding associated modulated subpupils 32′ of the subpupilmodulator 30, 30.2, 30.3, 30.4, 30.5 is controlled responsive thereto,and possibly further responsive to input from a particular user 22 instep (6706) so as to provide for a desired level of overall brightnessof the perceived associated virtual image 16′″.

Notwithstanding the prospective reduction in power as a result of themodulation of variable-intensity light-source elements 100 associatedwith realized exit subpupil 32″, it is possible that one or more regionsof activated exit subpupils 32, 32″ might be larger than the eye pupil38, and therefore, not as susceptible to benefit from intensitymodulation as would be sufficiently smaller exit subpupils 32, 32″ of arelatively-more-ideal associated optical subsystem 14, 14.2, 14.3, 14.4,14.5, 14.6, 14.7 for which all of the light 16′ from a singlelight-source element 100 might pass entirely through the eye pupil 38,so as to provide for deactivating other exit subpupils 32, 32″. However,from an analysis of one set of embodiments, operating in cooperationwith typical locations and extents (diameters) of an eye pupil 38, evenwithout optimizing the use of variable-intensity light-source elements100, it was found that approximately 60 to 80 percent of thelight-source elements 100 could be deactivated at any given time,demonstrating the prospect of a relatively-wide field-of-view near-eyedisplay system 10 incorporating relatively simple and realisticcomponents in a relatively-compact arrangement, particularly if theoptical path between the light-source elements 100 and the exit pupil 18is folded with one or more reflective surfaces, infra.

The diameter of a typical eye pupil 38 is in the range of 2 to 8millimeters, and is responsive to the overall intensity of the virtualimage 16′″, wherein the diameter/size of the eye pupil 38 is inverselyrelated to the brightness of the virtual image 16′″, as would thediameter/size of the associated Active Subpupil Region (ASR) 72, thelatter of which provides for deactivating relatively-more exit subpupils32, 32″ in association with a relatively-brighter virtual image 16′″than for a relatively-dimmer virtual image 16′″.

Each exit subpupil 32, 32″ is a collection of light 16′ from, and inone-to-one correspondence with, a corresponding modulated subpupil 32′,for example, but not limited to, a real image of the modulated subpupil32′. For the first aspect near-eye display system 10, 10.1, themodulated subpupil 32′ corresponds to a light-modulating pixel 60 of anassociated flat-panel two-dimensional modulation array 58. For asecond—10.2, or third—10.3 aspect near-eye display system 10, 10.2, 10.3the modulated subpupil 32′ corresponds to a light-source element 100 ofan associated controllable light source 97. For the fourth aspectnear-eye display system 10, 10.4, the modulated subpupil 32′ correspondsto a modulation element 90 of an associated controllable light source97. For the fifth-aspect near-eye display system 10, 10.5, the modulatedsubpupil 32′ corresponds to a light-emitting pixel 54 of an associatedwaveguide projector 152.

The size, shape, and intensity profile of each exit subpupil 32, 32″depends upon a) the size, shape, and intensity profile the associatedsource of light 104 at the associated modulated subpupil 32′; b) theability of the associated optical subsystem 14, 14.1, 14.2, 14.3, 14.4,14.5, 14.6, 14.7 to form an image of the modulated subpupil 32′; and c)the transverse location of the modulated subpupil 32′ relative to theoptical axis 36 of the optical subsystem 14, 14.1, 14.2, 14.3, 14.4,14.5, 14.6, 14.7, i.e. the degree to which the modulated subpupil 32′ ison- or off-axis relative to the optical axis 36, wherein an on-axis exitsubpupil 32, 32″ would likely have better image quality than an off-axisexit subpupil 32, 32″.

For relatively-smaller exit subpupils 32, 32″—even if relatively blurredby either an imperfect optical subsystem 14, 14.1, 14.2, 14.3, 14.4,14.5, 14.6, 14.7 or a misalignment between user 22 and the near-eyedisplay system 10—relatively more exit subpupils 32, 32″ would likely beoutside the Active Subpupil Region (ASR) 72 and therefore subject todeactivation, so as to provide for a relatively greater power savings.Although generally, relatively-smaller exit subpupils 32, 32″ arebeneficial, practical limits either on a) the density of associatedpixels 60, 54 or light-source elements 100, or b) the performance of theassociated optical subsystem 14, 14.1, 14.2, 14.3, 14.4, 14.5, 14.6,14.7, or an associated user-caused misalignment thereof, can limit thelower bound on the size of the exit subpupils 32, 32″. For example, inone set of embodiments, a diameter of exit subpupils 32, 32″ in therange of 0.5 to 2.0 millimeters is beneficial because: a) a largerdiameter would imply greater overlap of adjacent exit subpupils 32, 32″and thereby involve relatively more complex mapping and intensitycontrol of any of the second—through fourth—aspect subpupil modulationcontrol process 6300, 6600, 6700; b) a diameter in the range of 0.5 to2.0 millimeters would be sufficiently smaller than the eye pupil 38 soas to provide for utilizing an Active Subpupil Region (ASR) 72 with asingle exit subpupil 32, 32″ located within the eye pupil 38 so as toprovide for maximum power savings; and c) for a smaller diameter,maintenance of a proper image of a point light source would bechallenging to implement, and likely not cost effective, even with arelatively good optical subsystem 14, 14.1, 14.2, 14.3, 14.4, 14.5,14.6, 14.7, particularly when subject to an associated user-causedmisalignment thereof.

Referring again to FIGS. 59a and 59b , an ideal optical subsystem 14forms a real image of each modulated subpupil 32′ as a correspondingidealized exit subpupil 32, possibly with magnification, that is focusedon the surface 18″ of the exit pupil 18, i.e. the subpupil surface 84,which in turn is aligned with the eye pupil 38 and which conforms to thefront surface 20′ of the eye 20. However, referring again to FIG. 59c ,for an optical subsystem 14 with imperfect optical components, or for asubpupil surface 84 that is either misaligned with respect to the eyepupil 38 or that does not conform to the front surface 20′ of the eye20, the resulting realized exit subpupil 32″, to first order, might bean effectively blurred image of the associated modulated subpupil 32′,for which adjacent realized exit subpupils 32″ of an array of realizedexit subpupils 32″ associated with a corresponding array of modulatedsubpupils 32′ of an associated subpupil modulator 30 might overlap withone another, particularly given the typically minimal practicalseparation between adjacent modulated subpupils 32′, for example,adjacent light-source elements 100. If such blurring and overlapping isrelatively consistent across the subpupil surface 84 then the user 22will not see significant differences in intensity as the eye pupil 38 isrotated and directed at different locations of the virtual image 16′″provided that no light 16′ from a deactivated exit subpupil 32, 32″would have reached the eye pupil 38 if activated or, in other words,provided that the Active Subpupil Region (ASR) 72 is sufficiently largeto prevent such a condition. However, the larger the size of the exitsubpupil 32, 32″, the greater the likelihood of more exit subpupils 32,32″ overlapping the eye pupil 38, and therefore the larger the size ofthe Active Subpupil Region (ASR) 72 would need to be in order topreclude that condition from occurring. If the region occupied by theexit subpupil 32, 32″ was entirely outside the eye pupil 38, then thedeactivation thereof would not have an impact on the perceivedbrightness of the virtual image 16′″. Accordingly, one method ofmitigating against a prospective perceived reduction in brightness ofthe virtual image 16′″ responsive to a prospective deactivation of exitsubpupils 32, 32″—absent a modification of the brightness of activatedexit subpupils 32, 32″, infra—would be to increase the size of theActive Subpupil Region (ASR) 72 so that only those exit subpupils 32,32″ that do not overlap with the eye pupil 38 would be subject todeactivation. Furthermore, as the size of the Active Subpupil Region(ASR) 72 is increased, a relatively lesser proportion of the exitsubpupils 32, 32″ are outside thereof and susceptible to automaticdeactivation to reduce power usage. Generally, exit subpupils 32, 32″having a diameter between 0.5 and 2.0 millimeters are beneficial becausethe size of the Active Subpupil Region (ASR) 72 would then need to beonly slightly larger than that of eye pupil 38 under the relativelysimplest implementation, for example, in accordance with the firstaspect subpupil modulation scheme 70, 70.1, supra, while alsoalternatively providing for a relatively smaller Active Subpupil Region(ASR) 72 in accordance either the third aspect subpupil modulationscheme 70, 70.3, supra, or any of the first-through fourth-aspectsubpupil modulation control processes 6100, 6300, 6600, 6700, supra.

In an extreme case, the exit subpupils 32, 32″ are not only blurredimages of their corresponding associated modulated subpupils 32′, butalso vary in size, shape and intensity profile (i.e. the profile ofpropagated optical ray density through each given point within thesubpupil) relative to one another as a result of passage throughdifferent portions of the optical subsystem 14. For example, it isanticipated that exit subpupils 32, 32″ formed from rays that propagatefrom a modulated subpupil 32′ that is relatively distal to the opticalaxis 36 of the optical subsystem 14 will be formed sub-optimally,resulting in a corresponding relatively-larger exit subpupil 32, 32″with a relatively non-uniform intensity profile relative to an exitsubpupil 32, 32″ associated with a modulated subpupil 32′ that isrelatively proximal to the optical axis 36. Under the first aspectsubpupil modulation scheme 70, 70.1, supra, if the Active SubpupilRegion (ASR) 72 is sufficiently large to encompass the entirety of suchsub-optimally-formed exit subpupils 32, 32″ that could overlap the eyepupil 38 by even a small amount, then the corresponding associatedmodulated subpupils 32′ would remain activated.

Referring to FIGS. 68 and 69, a sixth-aspect near-eye display system 10,10.6 is the same as the second aspect near-eye display system 10, 10.2,supra, except that the sixth-aspect near-eye display system 10, 10.6does not incorporate a first dioptric-power optical element 56, 56.1,56.1′, L₁, and, instead of a second dioptric-power optical element 56,56.2, 56.2′, L₂, the sixth-aspect near-eye display system 10, 10.6incorporates at the same relative location—i.e. between the flat-paneltwo-dimensional image-display modulation array 94 and the associatedexit pupil 18—a catadioptric magnifier 170 as the associatedeighth-aspect optical subsystem 14, 14.8. Accordingly, the associatedflat-panel two-dimensional image-display modulation array 94 cooperatesdirectly with the controllable light source 97/flat-paneltwo-dimensional light-source array 98 as the associated seventh-aspectimage generator 12, 12.7 that provides for generating the light 16′ ofthe virtual image 16′″ by modulating the light 104 from the controllablelight source 97. The catadioptric magnifier 170—also referred to as a“pancake lens”—incorporates an internally-folded optical path in acompact form that provides for relatively-high image quality and arelatively-large field-of-view in a relatively-compact arrangement ofrefractive, reflective and polarization components, for example, asdescribed in the following references, each of which is incorporated byreference in its entirety: “Folded optics with birefringent reflectivepolarizers” by Timothy L. Wong, Zhisheng Yn, Gregg Ambur and Jo Etter,Porc. SPIE 10335, Digital Optical Technologies 2017, 103350E (26 Jun.2017); doi;10.1117/12.2270266; and U.S. Pat. No. 3,940,203 to JosephAnthony La Russa, issued on 24 Feb. 1976.

More particularly, referring to FIG. 69, the catadioptric magnifier 170incorporates first 172, second 174, and third 176 dioptric elements,oriented with a first surface 172.1 (also designated as the S1 surface)of the first dioptric element 172 facing the exit pupil 18, a secondsurface 172.2 (also designated as the S2 surface) of the first dioptricelement 172 facing a first surface 174.1 (also designated as the S3surface) of the second dioptric element 174, a second surface 174.2(also designated as the S4 surface) of the second dioptric elementfacing a first surface 176.1 of the third dioptric element 176, and asecond surface 176.2 (also designated as the S6 surface) of the thirddioptric element 176 facing the flat-panel two-dimensional image-displaymodulation array 94. A reflective linear polarizer 178 and aquarter-wave plate 180 are located between the first 172 and second 174dioptric elements and abutting one another, with the reflective linearpolarizer 178 also abutting the second surface 172.2 of the firstdioptric element 172, and the quarter-wave plate 180 also abutting thefirst surface 174.1 of the second dioptric element 174. The reflectivelinear polarizer 178 provides for reflecting light of a first directionof linear polarization, and provides for transmitting light of a seconddirection of linear polarization that is relatively orthogonal to thefirst direction of linear polarization. The quarter-wave plate 180provides for converting linearly-polarized light to circularly-polarizedlight, and can provide for converting circularly-polarized light tolinearly-polarized light, as described in U.S. Pat. No. 3,940,203. Thesecond surface 176.2 of the third dioptric element contains a reflectivecoating 182 (e.g. half silvered), for example, in one set ofembodiments, that provides for reflecting about half of the lightincident thereupon. In cooperation with the illustrated catadioptricmagnifier 170, the sixth-aspect near-eye display system 10, 10.6 isconfigured so that light 16′ entering the catadioptric magnifier 170from the flat-panel two-dimensional image-display modulation array 94 ispreconditioned to be circularly polarized. In one set of embodiments,the first 172, second 174, and third 176 dioptric elements are made ofinjection-moldable acrylic, for example, for the second 174, and third176 dioptric elements, with minimum birefringence.

In operation of the sixth-aspect near-eye display system 10, 10.6, halfof the circularly-polarized light 16′ from the flat-paneltwo-dimensional image-display modulation array 94 incident upon the S6surface is reflected and lost. The remaining light 16′ is transmittedthrough the S6 surface and subsequently refracted at the S5 surface andthen refracted at the S4 surface, and then subsequent transmittedthrough the S3 surface and the quarter-wave plate 180 in abutmenttherewith, which converts the circularly-polarized light 16′ tolinearly-polarized light 16′ having the first direction of linearpolarization, which is then reflected by the reflective linear polarizer178 in abutment with the quarter-wave plate 180. The reflectedlinearly-polarized light 16′ is then again transmitted a second timethrough the quarter-wave plate 180 and converted thereby tocircularly-polarized light 16′, which is then refracted by the S4surface and then refracted by the S5 surface, after which, half of thatcircularly-polarized light 16′ is internally reflected by the reflectivecoating 182 on the S6 surface, with the remainder of that light 16′being transmitted through the S6 surface and lost. The internallyreflected light 16′—circularly polarized, but of opposite handedness tothe light 16′ that was initially incident upon the catadioptricmagnifier 170—is then refracted by the S5 surface and then refracted bythe S4 surface, and then transmitted through the S3 surface and thentransmitted a third time through the quarter-wave plate 180 andconverted thereby to linearly-polarized light 16′, but having the seconddirection linear polarization, so as to provide for that light 16′ to betransmitted through the reflective linear polarizer 178, thentransmitted through the S2 surface, and finally refracted by the S1surface for propagation to the exit pupil 18, after having beentransmitted three times through each of the S4 and S5 surfaces.

It should be understood that the particular configuration of thecatadioptric magnifier 170 illustrated in FIGS. 68 and 69, —anddescribed hereinabove to provide a general description of howrefractive, reflective and polarization elements can work in amulti-pass catadioptric arrangement as a catadioptric magnifier 170, —isnot limiting, and that other polarization implementations, assignmentsof polarization and reflective surfaces and types and numbers ofelements may be applied to effectively create other embodiments of acatadioptric magnifier 170 in accordance with the sixth-aspect near-eyedisplay system 10, 10.6.

In accordance with a first stage of an associated design process, thecatadioptric magnifier 170 illustrated in FIGS. 68 and 69 was designedusing a similar optical design process as described hereinabove forother lenses of the near-eye display system 10, with associated designparameters of virtual image field of view, apparent distance to thatvirtual image, design entrance pupil (i.e. ultimately the exit pupil ofthe optical system), and the distance from exit pupil to the magnifier,and, to support moldability, using an acrylic material for the first172, second 174 and third 176 dioptric elements, with a space providedfor between the second 174 and third 176 dioptric elements, with the S2and S3 surfaces each constrained to be a flat surface that was common toboth so as to better support the application of a reflectivepolarization surface between the first 172 and second 174 dioptricelements as a bonded doublet, and with a flat surface representing theflat-panel two-dimensional image-display modulation array 94. For designpurposes, the exit pupil 18 was treated as a design entrance pupil 141for the optical simulation of light rays traveling forward therefrom, toand through the first 172, second 174 and third 176 dioptric elements,and onto the flat surface representing the flat-panel two-dimensionalimage-display modulation array 94. The S6 surface was modeled as amirror for the first pass of light traveling forward from the designentrance pupil 141 through the first 172, second 174 and third 176dioptric elements, and the common, flat S2/S3 surface was modeled as amirror for the second pass. Effectively the design process thereforeincludes passing light from the exit pupil 18/design entrance pupil 141,through all each of the first 172, second 174 and third 176 dioptricelements, then reflecting from the S6 surface to pass again but inreverse back successively through the third 176 and second 174 dioptricelements, then reflecting from the flat S2/S3 surface to pass again in aforward direction successively through the second 174 and third 176dioptric elements to form an image at the location of the flat-paneltwo-dimensional image-display modulation array 94, with the goal offorming a best image of the virtual image thereat. The optical designtherefore involves seven total elements for design purposes, wherein thevarious surfaces are constrained to represent common elements as thelight interacts therewith.

In a second stage of the optical design process, the optical subsystem14, 14.8 may then be modeled in combination with additional opticalelements to account for passage of light rays through the flat-paneltwo-dimensional image-display modulation array 94 and back to thecontrollable light source 97 of the flat-panel two-dimensionallight-source array 98, using the entrance pupil 28′ as the design object138, and utilizing a process similar to the conditioner-lensprescription design process 5000 to determine an optimum image of theentrance pupil 28′ as a modulation surface 92 of the controllable lightsource 97 of the flat-panel two-dimensional light-source array 98.

As an alternative to the first stage of the design process, the lightrays through the flat-panel two-dimensional image-display modulationarray 94 from the first stage of the design process may be continuedtherethrough to a new geometric surface and aperture 28 which can bemodeled as a retroreflective surface (i.e. a phase conjugation surface)wherefrom the optical rays retroreflect back to the flat-paneltwo-dimensional image-display modulation array 94. In other words, anyray striking that surface is exactly reversed, and the final geometricimage at the flat-panel two-dimensional image-display modulation array94 is exactly that of the first intermediate image passing through theflat-panel two-dimensional image-display modulation array 94. Theseretroreflected rays for purposes of the design would be identical to therays from the flat-panel two-dimensional image-display modulation array94 to the controllable light sources 97.

The optical subsystem 14, 14.8 can therefore be optimized for best imagequality using the final surface as the image location (which similarlyresults in the intermediate image being optimized) while also possessinga surface within that optical subsystem where the lighting surface canbe located. Appropriate parameters such as the distance from theflat-panel two-dimensional image-display modulation array 94 to themodulation surface 92 of the flat-panel two-dimensional light-sourcearray 98 can then be varied to reach an optimized overall solutionidentifying the best location of that modulation surface 92 of theflat-panel two-dimensional light-source array 98.

With the merit function of the design used to provide for a best imageof the virtual image. additional operands in the merit function canprovide a preference for a smallest size of that retroreflectingaperture while allowing the distance from the flat-panel two-dimensionalimage-display modulation array 94 to that aperture 28 to vary, withoptimization thereof to provide for the smallest, and therefore mosteconomical and compact, two-dimensional array 26 of controllable lightsources 97 within that aperture 28. One can further adjust the relativeweights of the quality of the image formed at the flat-paneltwo-dimensional image-display modulation array 94 with the size andspacing of the two-dimensional array 26 of controllable light sources 97within the associated aperture 28 so as to provide for the most compactdesign. Notwithstanding that such an approach may not result in ahigh-quality image of the two-dimensional array 26 of controllable lightsources 97 at the desired exit pupil 18, it nonetheless provides atleast some ability to reduce intensities of those controllable lightsources 97 so as to provide for reducing power consumption while bestexploiting the advantages of a multi-pass catadioptric magnifier 170.

Referring to FIG. 68, optical rays from three different points 184.1,184.2, 184.3 on the surface 18″ of the exit pupil 18 are traced back tocorresponding respective regions 186.1, 186.2, 186.3 on the modulationsurface 92 of the flat-panel two-dimensional light-source array 98.Whereas these regions 186.1, 186.2, 186.3 do not represent high-qualityimages of the corresponding respective points 184.1, 184.2, 184.3 on thesurface 18″ of the exit pupil 18, they can provide for control of theexit subpupils 32, 32″ to provide for reducing power consumption andreflection of extraneous light 16 ^(iv) as described hereinabove,without need for an additional conditioner lens 102, 102′, 132, L₁ tootherwise create such bounding regions within the associated modulationsurface 92. Accordingly, the ray traces illustrate the feasibility of amodulation surface 92 of associated controllable light sources 97, eachof which fully illuminates the entirety of the flat-paneltwo-dimensional image-display modulation array 94 while alsocollectively filling the exit pupil 18.

Furthermore, referring to FIG. 69, a relatively-smaller region in theexit pupil 18 bounded by the first 184.1 and second 184.2 points thereincorrespond to a corresponding relatively-smaller region—bounded by thecorresponding first 186.1 and second 186.2 regions therein—within themodulation surface 92 of associated controllable light sources 97.Accordingly, for a given position of the eye pupil 38, each light-sourceelement 100 not having rays that reach the eye pupil 38 can bedeactivated, together with activation of the remaining light-sourceelements 100 that have at least some rays that reach to the eye pupil38. Furthermore, in cooperation with an advanced mapping of the opticalsubsystem 14, 14.8 to account for the effect of location and extent ofthe eye pupil 38, light-source elements 100 for which a relatively-lowpercentage of light rays therefrom would pass through the eye pupil 38,can be either dimmed or deactivated, while also relatively increasingthe intensity of light-source elements 100 for which a relatively-highpercentage of light rays therefrom would pass through the eye pupil 38,wherein each light-source element 100 is itself illuminating theentirety of the flat-panel two-dimensional image-display modulationarray 94 so that the virtual image 16′″ viewed by the user would be acomposite of the components of the virtual image 16′″ illuminated byeach of the active light-source elements 100.

Referring to FIGS. 18, 19, 31, 32, and 45 through 47, it should beunderstood that the associated curved two-dimensional light-source array106 of the third aspect near-eye display system 10, 10.3, and the curvedlight-redirecting surface 110 of the fourth aspect near-eye displaysystem 10, 10.4 are beneficial independent of the cooperation thereofwith the associated subpupil modulator 30 and associated subpupilmodulation processes, i.e. beneficial for illumination of an associatedflat-panel two-dimensional image-display modulation array 94 to generatea corresponding virtual image 16′″ and illuminate an exit pupil 18therewith, by virtue of providing for the formation of exit pupil 18having a concave-curved surface 18″ that better conforms to the frontsurface 20′ of the eye 20, so as to provide for maintaining focusindependent of the rotational position of the eye pupil 38.

Furthermore, in respect of the third aspect near-eye display system 10,10.3 illustrated in FIGS. 18, 19, 45 and 47, when the curvedtwo-dimensional light-source array 106 incorporates non-isotropiclight-source elements 100, for example, light-emitting-diode elements100′ that typically exhibit directivity, the curvature of the underlyingconcave-curved surface 107 provides for light 104 from eachlight-emitting-diode element 100′ to emanate in a direction that isnormal to the underlying concave-curved surface 107, so as to providefor a relatively-higher degree of uniformity of the illumination of thevirtual image 16′″ relative to that which would otherwise be providedfor by a flat-panel two-dimensional light-source array 98.

For example, referring to FIG. 70, illustrating a typical luminousintensity distribution of a light-emitting diode for both horizontal (H)and vertical (V) directions of illumination, a light-emitting-diodeelement 100′ has sufficiently high directivity that if used in aflat-panel two-dimensional light-source array 98, for example, asillustrated in FIG. 17 for the second aspect near-eye display system 10,10.2, the angle, relative to the surface normal, of the relativelycentral optical ray from each light-emitting-diode element 100′ thatpasses through the center of the flat-panel two-dimensionalimage-display modulation array 94 increases with increasing distance ofthe light-emitting-diode element 100′ from the optical axis 36,resulting in a corresponding reduction in brightness of that portion ofthe virtual image 16′″ with increasing distance of the correspondingmodulated subpupil 32′ from the optical axis 36, causing a variation inthe perceived brightness uniformity of the virtual image 16′″ as afunction of the location of the exit subpupil 32, 32″. In other words,if illuminated by a flat-panel two-dimensional image-display modulationarray 94 of relatively-highly directive associated light-source elements100, 100′, the brightness of the virtual image 16′″ will be higher in aparticular area of the virtual image 16′″, gradually fading to a lowerbrightness around that relatively higher brightness area, with thelocation of that area of relatively higher brightness changing as theeye pupil 38 is directed at different image locations.

However, locating the relatively-highly directive light-source elements100, 100′ on an underlying concave-curved surface 107 provides forsignificantly less deviation of the central optical ray from the surfacenormal, at any point across the entire curved two-dimensionallight-source array 106. Accordingly, as the eye pupil 38 receives lightfrom different areas of the concave lighting surface for different gazedirections 34, the center of the perceived virtual image 16′″ is stillreceiving light from that concave lighting surface which issubstantially normal to that surface. Notwithstanding there still may bean area of the virtual image 16′″ of relatively-higher brightness due toa reduction in intensity from a light-source element 100, 100′ as afunction of angle from the surface normal, that area ofrelatively-higher brightness will remain relatively fixed as the eye 20rotates and therefore, if desired, can be compensated for byconventional means such as an overall intensity spatial profileadjustment of the virtual image 16′″ shown on the flat-paneltwo-dimensional image-display modulation array 94, or the inclusion of agradient filter. In addition to providing for greater uniformity inperceived intensity responsive to rotation of the eye 20, the curvedtwo-dimensional light-source array 106 also provides for a moreefficient utilization of the light 104 generated by the light-sourceelements 100, 100′.

Generally, the angular-dependent output of light-source elements 100,100′ can cause a “hot spot” of relatively higher perceived imagebrightness at the flat-panel two-dimensional image-display modulationarray 94 through which the primary axis of the light-source element 100,100′ passes. Accordingly, whereas the entire virtual image 16′″ will beseen through the eye pupil 38 regardless of the gaze direction 34, this“hot spot” of higher brightness will move around in the virtual image16′″ if these intersections of primary axes of different light-sourceelements 100, 100′ with the corresponding flat-panel two-dimensionalimage-display modulation array 94 locations, vary with gaze direction34. But if all those intersections are at the same spot, for example,generally the center of the flat-panel two-dimensional image-displaymodulation array 94, then the “hot spot” will be in the same locationregardless of gaze direction 34. An appropriate curvature of theunderlying concave-curved surface 107 provides for these normaldirections to align with those intersections. This curvature may notnecessarily be the best for forming a concave-curved subpupil surface84, 84″ matching that of the front surface 20′ of the eye 20, but thereis certainly a synergy in providing a concave curvature for at leastsome benefit towards both goals.

It should be understood, that any reference herein to the term “or” isintended to mean an “inclusive or” or what is also known as a “logicalOR”, wherein when used as a logic statement, the expression “A or B” istrue if either A or B is true, or if both A and B are true, and whenused as a list of elements, the expression “A, B or C” is intended toinclude all combinations of the elements recited in the expression, forexample, any of the elements selected from the group consisting of A, B,C, (A, B), (A, C), (B, C), and (A, B, C); and so on if additionalelements are listed. Furthermore, it should also be understood that theindefinite articles “a” or “an”, and the corresponding associateddefinite articles “the” or “said”, are each intended to mean one or moreunless otherwise stated, implied, or physically impossible. Yet further,it should be understood that the expressions “at least one of A and B,etc.”, “at least one of A or B, etc.”, “selected from A and B, etc.” and“selected from A or B, etc.” are each intended to mean either anyrecited element individually or any combination of two or more elements,for example, any of the elements from the group consisting of “A”, “B”,and “A AND B together”, etc. Yet further, it should be understood thatthe expressions “one of A and B, etc.” and “one of A or B, etc.” areeach intended to mean any of the recited elements individually alone,for example, either A alone or B alone, etc., but not A AND B together.Furthermore, it should also be understood that unless indicatedotherwise or unless physically impossible, that the above-describedembodiments and aspects can be used in combination with one another andare not mutually exclusive. Accordingly, the particular arrangementsdisclosed are meant to be illustrative only and not limiting as to thescope of the invention, which is to be given the full breadth of theappended claims, and any and all equivalents thereof.

What is claimed is:
 1. A near-eye display system, comprising: a. anoptical subsystem, wherein said optical subsystem provides forprojecting light of a virtual image of image content to an eye location,and said optical subsystem provides for collecting said light of saidvirtual image propagating from an aperture of said optical subsystemonto an exit pupil on a surface proximate to an outer surface of an eyewhen said eye is at said eye location; and b. a subpupil modulatorwithin said aperture, wherein said subpupil modulator in cooperationwith said optical subsystem provides for forming a plurality ofsubpupils within said exit pupil, at least two of said plurality ofsubpupils overlap one another by at least 20% within said exit pupil,said subpupil modulator in cooperation with said optical subsystemprovides for projecting to said eye location a portion less than all ofsaid light of said virtual image associated with one or more less thanall of said plurality of subpupils, said light of said virtual image isgenerated by a controllable light source of said subpupil modulator,said controllable light source of said subpupil modulator provides forseparately and controllably illuminating or not illuminating eachsubpupil of said plurality of subpupils, said virtual image is generatedby a flat-panel two-dimensional image-display modulation array oflight-modulating image-display pixels that is illuminated by saidcontrollable light source, and said optical subsystem comprises acatadioptric magnifier located between said flat-panel two-dimensionalimage-display modulation array and said exit pupil, wherein saidcatadioptric magnifier provides for collecting said light of saidvirtual image propagating from said subpupil modulator onto said surfaceof said exit pupil.
 2. A near-eye display system as recited in claim 1,wherein said catadioptric magnifier comprises a folded opticincorporating at least one reflective surface.
 3. A near-eye displaysystem as recited in claim 1, wherein said catadioptric magnifierprovides for said light of said virtual image to pass at least threetimes through at least one surface of said catadioptric magnifier.
 4. Anear-eye display system, comprising: a. an optical subsystem, whereinsaid optical subsystem provides for projecting light of a virtual imageof image content to an eye location, and said optical subsystem providesfor collecting said light of said virtual image propagating from anaperture of said optical subsystem onto an exit pupil on a surfaceproximate to an outer surface of an eye when said eye is at said eyelocation; and b. a subpupil modulator within said aperture, wherein saidsubpupil modulator in cooperation with said optical subsystem providesfor forming a plurality of subpupils within said exit pupil, saidsubpupil modulator in cooperation with said optical subsystem providesfor projecting to said eye location a portion less than all of saidlight of said virtual image associated with one or more less than all ofsaid plurality of subpupils, said subpupil modulator provides forindividually and independently controlling an intensity of said lightthrough each activated subpupil of said plurality of subpupils to alevel less than a maximum level of intensity, said light of said virtualimage is generated by a controllable light source of said subpupilmodulator, said controllable light source of said subpupil modulatorprovides for separately and controllably illuminating or notilluminating each subpupil of said plurality of subpupils, said virtualimage is generated by a flat-panel two-dimensional image-displaymodulation array of light-modulating image-display pixels that isilluminated by said controllable light source, and said opticalsubsystem comprises a catadioptric magnifier located between saidflat-panel two-dimensional image-display modulation array and said exitpupil, wherein said catadioptric magnifier provides for collecting saidlight of said virtual image propagating from said subpupil modulatoronto said surface of said exit pupil.
 5. A near-eye display system asrecited in claim 4, wherein said catadioptric magnifier comprises afolded optic incorporating at least one reflective surface.
 6. Anear-eye display system as recited in claim 4, wherein said catadioptricmagnifier provides for said light of said virtual image to pass at leastthree times through at least one surface of said catadioptric magnifier.